How old is 30, really?

So I'm 16. This is probably because in young and I've kind of been insecure about my age as of recently, but I've been thinking about this a lot.

I want to be a doctor. I really want to be a doctor. Specifically a Forensic Pathologist. But that takes ages, assuming everything goes according to plan(and with med school acceptance rates, I can't bet on that) I'll be 28 by the time I'm ab attending. (Graduaing high-school a year early and trying to do the same with my bachelor's). Which is young for a doctor, but is still old compared to most professions. And it's just been worrying me. I know your life doesn't stop during med school and residency, but most of your time and energy is spent doing that. It'd require sacrifice. I'm prepared to make that sacrifice because I don't think I'd be happy with any other job. But it's still a daunting idea. I'll be 29 when I'm properly "free".

I'll be 29 when my life properly "starts".

I feel old NOW at 16, God how will I feel then? I struggle thinking of what I'd be like theb. It's almost depressing. I'm just trying to grapple with the commitment I'd have to make.

I'm worried about all that I'll miss out in. I'm not that social, so I'm not worried about losing friends out of it. I'm worried about loosing myself. What will happen to my hobbies, my interests? I guess that's a worry I have for adult life in general. Everyone seems so sad, it isn't exactly a tempting idea. My mom's 48 and she's depressed because she feels like her life's over. I don't want to be like that. I don't want to hate my life that much.

I've just been thinking about it all.