I feel old. Goddamn it

Talking to my friend from High School at Uni today I realized that being in my forth year of university (in New Zealand, most people are done in three) that a high proportion of the first-years are so young that I now have memories that are now older than them. With that I felt like am am getting old. This shouldn't be happening. I turned twenty-one two weeks ago, and yet I still felt like I am getting old. Why is this. Am I just being a melodramatic kid who's having a moment. Possibly. Is my depression getting to me. Likely. Is it because I was supposed to have an economics degree at the end of last year but now won't my Political Science and Media degree until the end of next year and am now fearing that i'll be irrelevant by the time i'm actively on the job market. That makes sense. Is it because I feel like too many milestones in life have come, gone, and passed me by and what's coming is terrifying and I am unsure on how to handle it. Probably. Am I just tricking myself to feel old so I don't feel too much like a child. Reading this back it sure sounds like it.

Thanks for putting up with my rant.