Hello, kudos to you for wanting a career change and having the financial ability to realize your dream!
First of all, do not get another degree since you already have one. Just take the minimal amount of prereqs! Ignore schools' "recommended" courses such as histology. Taking only the prereqs will take you 1.5 years, while getting a BS in science may be double the amount. It's definitely not worth it unless, of course, you want a career in science to be your Plan B or, you want to boost your overall GPA.
As an University of Waterloo student, I also contemplated about going to the optometry program there. I was also non-traditional in the sense that I was majoring in engineering. So given my background, I feel I can really relate to your situation.
I discovered that I didn't really like engineering as much as I hoped, so I was extremely enthusiastic when I discovered about optometry. The prospect of treating eye diseases excites me. The idea of owning my own practice seemed very gratifying. In addition, my first shadowing experience with a prosperous PP went really well. Not surprisingly, I was on fire about optometry for the longest time, until I learned about some of the negatives of this field.
You can imagine my anger when I learned what one of my mom's friends said about my new career resolution. "Optometry? Isn't that where people who can't get into med school go to? Don't let your kid go there!" Of course, I don't care about trivial things like this, but I did question why the admission GPA for opto school and med school are so different. From years of life experience, I humbly believed that while admission GPA does not paint the whole picture, it does have a correlation with how desirable and fought-after a career option is (analogous with a fought-after job and its corresponding high requirements). However, I was almost afraid to research--I was afraid that I would discover something about optometry that would change my mind because I was so fixated on it. Eventually, I came to my senses and did extensive research. I learned many things, such as the fact that most of a typical optometrist's earning comes from glasses. I also learned about the oversupply, the competition between opticians, optometrists, and ophthalmologists for the same "pie", the fact that optometrists are not needed in many countries (eg. Singapore), the BC province's new policy, and facts about commercial optometry that seems to be dominating. Not only that, I went out and shadowed 5 more optometrists, 2 in PP, 2 in Lenscrafter, and 1 in Walmart. I watched their typical days, helped out around the offices, and asked them a lot of questions about their profession. After all these, I became sufficiently educated about optometry and decided it's not for me since I wanted to treat eye problems without too much commercial aspect of the profession. On the other hand, I have a friend who loves the business aspect of optometry and is now attending SUNY. So, it's really about what YOU want, and whether optometry would meet your goals. Do a lot of research, and shadow a lot of people, even if it seems like a lot of work - Besides, the research and esp. shadowing will boost your application, so it's a win-win thing to do.
As for your age, I don't think you're too old or anything. Lots of people change their careers in their 30s and 40s. I've bumped into silver-haired people in faculty offices, thinking they were professors, only to realize they were still completing their Ph.D.s, haha.
At almost the same time, I was shadowing dentists and learning about their profession as well. I came to the conclusion that dentistry is a better fit for me. I'm in the process of applying to schools right now and it's very stressful, but at last, I feel I found the career that wouldn't leave me wondering if I'd be happier doing something else. I really wish you the best in your quest to career change. 4 years is a big investment. Please feel free to ask me any questions regarding the application as a non-trad or anything else if you want. Good luck!
