I've never really sat down and told anyone what it's been like, not only being the oldest person in my medical school class, but the oldest in every course I've taken since 1998. The truth is, I'm not sure I know, because I've never really regarded age as the defining factor in my experience as a medical student. For one thing, somebody has to be the oldest, even if it's only a matter of having been first out of the birth canal by a few seconds. It just so happens I was out and about a little earlier than the rest. For a guy who's had trouble being on time ever since, this is really pretty comical.
What I discovered right off, as the oldest, it's kind of hard to be invisible. Being over six feet tall and prone to verbal expression doesn't help; people tend to notice you whether it's intentional or not. If you're 20 something, along with a majority of your classmates, you can fade into the background. Not so for the "old guy." At the same time, this is an advantage because you don't have to worry about being memorable when it comes time to solicit letters of recommendation. You have a built-in singularity and people will remember you, for better or worse (hopefully not the case).
There are pressures associated with being the oldest or among the oldest. Since you're filling a space that would ordinarily be filled by a younger student, you have to demonstrate a genuine commitment to medicine. It could be presumed, because you're older, that you're having a mid-life crisis or merely wish to dangle your toes in the water, and since a tremendous amount of money and energy has been invested in your education, you'd better be worthy of it. Even though your presence is evidence the admissions committee took you seriously, you still have to prove yourself. There's no free ride simply because you may have been accomplished in the real world.
Then there is the question of who you'll associate with, who are going to be your friends. This is where mindset begins coming into play. If your self-image is strongly tied to your age and former social status, I think it's easy to create problems where there needn't be any. Sometimes we have to revise our ideas about ourselves to make room for flexibility. This may be highly individualized, but even before coming here many of my closest friends were younger than me, and in an environment where everyone was younger, being flexible was the only way to go, and I've had great fun as a consequence.
One question I often get is, "Don't you get treated like 'Dad' a lot?" To be completely honest, the answer is no. I don't think I'm deceiving myself here, because I've been trained to use my own emotional impressions in psychotherapy to gauge what's happening with patients. Had I chosen to act like a parent, it may have been different, but I'm not here because I haven't had children; I'm here to become a doctor just like the 25 year old sitting next to me. You get what you look for and if you expect to be regarded as a parental figure, don't be surprised if it happens. If you expect to be considered a peer and a friend and behave like one, that's generally what you'll get in return.
They say that medical school (graduate school of any sort) is a head game and whoever "they" are, they're dead right. When the going gets rough, and it does beginning day one, a person needs interior resources to draw upon. There absolutely has to be a comfort zone, a "fine and private place" within, that enables one to conceive of themselves as belonging, as meant to be here. Call it fate, desire, determination, the will of God -- we need a conviction that we're where we ought to be. Not where other people think we ought to be because of our age, gender, or any other superficial consideration, but where we know, at the core of our being, we're supposed to be. Once a person's got that, the rest is the same hard work that awaits everyone else. "Hot" or not (me).
