Is it dementia or just "old age"?

I would schedule a visit with a Neurologist.
Bring in all your notes as to what you have observed the past 12 months and any concerns that you might have.
It sounds like you have been doing a lot in order for mom to remain at home. If you were to go away for a week or two what would happen to mom? Would she be able to get groceries? Make dinner? Pay a bill if she had to? In an emergency could she or would she call 911 or would she call you?
Personally from what you have mentioned it does not sound like you mom should be living alone and she may even realize it herself.
How are her ADL's (Activities or Daily Living) Does she care for herself the way she did 1 year ago? 2 years a go? Or are some things slipping?

Certainly, there is a normal decline in cognitive functions as we age. However, this decline is mild and never disabling. In the early stages of dementias, the cognitive decline is similar to the one from normal aging. However, in dementia the symptoms continue to get worse by the day. This progression may be slow or rapid, but the worsening is undeniable. Eventually, the affected person loses all mental capacity to deal with the normal demands of daily life. In normal aging, there is a decline of sight and hearing, loss of muscular strength and balance. The decline of these functions, forces the person to slow down and many give up driving as a precaution. This is not dementia, it's normal because the person is aware of his/her limitations. The person with dementia doesn't know he has it. He might even want to drive. In normal aging the ability to reason is preserved. In dementia it is lost.

I have a 102.5 year old Aunt who reads the Wall Street Journal every day. The doctor who chalked up your Mom's very real issues to "just" old age should be fired by you and reported to the clinic's admin. Find a new doctor who will treat your mother with the dignity and respect she deserves.

A PCP who says all of this behavior is 'just old age' without giving your mom a MoCA cognizance exam is just GUESSING, in all honesty! In all likelihood, this PCP could administer the MoCA test himself; it's relatively simple, takes about 15 minutes, is composed of memory questions, other oral questions and a clock test where your mom would be asked to draw the face of a clock showing 3 pm or whatever. Scores on the MoCA range from zero to 30. A score of 26 and higher is considered normal. In the initial study data, normal controls had an average score of 27.4. People with mild cognitive impairment (MCI) scored an average of 22.1. People with Alzheimer's disease or progressive dementia had an average score of 16.2. During my mother's first testing, she scored an 18 and the doctors knew she had progressive dementia at that point & they were right; it's now 5 years later & she's in the advanced/late stages of dementia.

Ask your mother's PCP if he can and will administer this test before you do anything else, that's my suggestion. If he says no, move onto a neurologist, but they tend to give longer, more involved cognitive testing than the MoCA.

I will continue this post with a list of 10 warning signs of Alzheimer's/dementia which is good to note.

The 10 warning signs of dementia

Sign 1: Memory loss that affects day-to-day abilities
Are you, or the person you know, forgetting things often or struggling to retain new information?
It's normal to occasionally forget appointments, colleagues’ names or a friend’s phone number only to remember them a short while later. However, a person living with dementia may forget things more often or may have difficulty recalling information that has recently been learned.

Sign 2: Difficulty performing familiar tasks
Are you, or the person you know, forgetting how to do a typical routine or task, such as preparing a meal or getting dressed?
Busy people can be so distracted from time to time that they may forget to serve part of a meal, only to remember about it later. However, a person living with dementia may have trouble completing tasks that have been familiar to them all their lives, such as preparing a meal or playing a game.

Sign 3: Problems with language
Are you, or the person you know, forgetting words or substituting words that don’t fit into a conversation?
Anyone can have trouble finding the right word to express what they want to say. However, a person living with dementia may forget simple words or may substitute words such that what they are saying is difficult to understand.

Sign 4: Disorientation in time and space
Are you, or the person you know, having problems knowing what day of the week it is or getting lost in a familiar place?
It's common to forget the day of the week or one's destination – for a moment. But people living with dementia can become lost on their own street, not knowing how they got there or how to get home.

Sign 5: Impaired judgement
Are you, or the person you know, not recognizing something that can put health and safety at risk?
From time to time, people may make questionable decisions such as putting off seeing a doctor when they are not feeling well. However, a person living with dementia may experience changes in judgment or decision-making, such as not recognizing a medical problem that needs attention or wearing heavy clothing on a hot day.

Sign 6: Problems with abstract thinking
Are you, or the person you know, having problems understanding what numbers and symbols mean?
From time to time, people may have difficulty with tasks that require abstract thinking, such as using a calculator or balancing a chequebook. However, someone living with dementia may have significant difficulties with such tasks because of a loss of understanding what numbers are and how they are used.

Sign 7: Misplacing things
Are you, or the person you know, putting things in places where they shouldn't be?
Anyone can temporarily misplace a wallet or keys. However, a person living with dementia may put things in inappropriate places. For example, an iron in the freezer, or a wristwatch in the sugar bowl.

Sign 8: Changes in mood and behaviour
Are you, or the person you know, exhibiting severe changes in mood?
Anyone can feel sad or moody from time to time. However, someone living with dementia can show varied mood swings – from calmness to tears to anger – for no apparent reason.

Sign 9: Changes in personality
Are you, or the person you know, behaving in a way that's out of character?
Personalities can change in subtle ways over time. However, a person living with dementia may experience more striking personality changes and can become confused, suspicious or withdrawn. Changes may also include lack of interest or fearfulness.

Sign 10: Loss of initiative
Are you, or the person you know, losing interest in friends, family and favourite activities?
It's normal to tire of housework, business activities or social obligations, but most people regain their initiative. However, a person living with  dementia may become passive and disinterested, and require cues and prompting to become involved.

Becoming afraid of light traffic counld be anxiety? Would that be new for her, or has got worse?

I saw my Mother lose confidence with driving, shopping & making decisions. Over many months, more little areas of difference/decline were noticed. Then a TIA (suspect now there had been more). Anxiety was definately in the mix too.

A good thorough check up for bloods, BP, O2 etc should be done first with PCO. Inc a chat about aging, expectations, general well-being, leading ino mental health at that or a 2nd appointment.