How to adult?

I lived with the notion that on one of my birthdays, something will magically click, switching on an adult version of me inside – one that is mature, responsible, and wise. I thought it would happen on my eighteenth birthday – the "debut to adulthood".

Well, it didn’t. Bummer, I thought, but it was not the end of days. I had three more years of undergrad, plus probably a few more in the workforce, unless I get into grad school, that might jolt my inner adult awake. Probably.

College kept me on my toes with academics and org work (plus several fandoms on the side, but I digress), so turning into adult-me was not at the top of my laundry list of priorities. Life went on with me juggling school, org and dorm life.

In what felt like a haze in retrospect, I finally graduated in June 2015. Sure, I grew old and got my bachelor's degree, but I’m not entirely sure if I grew up. (Some would argue that I didn't because of my current love for a certain Marvel superhero, but that's another matter.) I didn't feel any instant significant change as to who I am; I was still just me.

Common sense tells me that such drastic change into a full-fledged adult is impossible. It also tells me that a better adult version of a person will not replace the younger one, as if only a temporary version of the self. It has been nagging at me to stop this wishful thinking, because becoming an adult is something I have to experience and grow into.

I can't help but shudder, today that I am officially 21, thinking about adulthood because I feel unprepared and uneasy. Or is it that I am not ready to face the music that I become anxious merely thinking of the future? Or have I actually entered adulthood prematurely but have to keep trudging in blind because I never knew?

Do I still wait for that change?