AHH, I turned 20 last month and I had a total freak-out too!
I just felt like I was too immature to actually be two decades old, and I couldn't deal with not having the "teenager" excuse to fall back on anymore. Then I got really cynical and realized that I'm not "growing up" anymore, I'm AGING. Ew.
And at the same time, I felt like I hadn't accomplished ANYTHING in two decades and that I was wasting my life.
It might have had something to do with my birthday falling in the middle of midterms- basically I was spaz.
Like a firework unexploded
Wanting life but never
knowing how