I remember starting my pre-reqs for med school when I was 23 and feeling old because I had quit law school to do it and was freaking out. I applied to a Physical Therapy program instead because it was quicker - I got in without the full slate of pre-reqs which would have taken me one more year likely. The PT program didn't work out because about a month into it, I realized that I hated using those measurement things and palpating bones and muscles all the time and oh, yeah, taking orders from MDs. Instead of going on to finish medicine, I went back to law school and ended up extremely jaded and miserable but making six figures when I was the ripe old age of 25.
I felt like 23 was too old! What an idiot! I recently started a PhD program in my 30s and kick myself every day because I am too old, but I am learning to silence my demons. I am a mom of 2 and married, now I really do feel old. 🙂 I think my current program is right for me, but medicine would have likely also worked back then. I think I would not be willing to do the residency now, but that's just me and where I am at in my life. I also wasn't willing to take on that debt. My PhD program is fully and well-funded, and I have saved for the endeavor.