Reassurance please 😅

Am I the only one who feels different after turning 18? My birthday was on Saturday and all my friends say nothing felt different for them. But for me it feels like everything has changed... I am in a private school and got the opportunity to stay a 5th year for teachers training, my boyfriend is joining the army and when he gets back from boot camp we are getting engaged (he's going infantry and could die. I'd rather not let him leave and not even get a chance to get to marry the man). It will be two months before my graduation so my principal is okay with it and I would be getting married in October of next year (since he'll have schooling before he leaves). Anyways, before I turned 18 it felt like I was just some kid making up big plans in my head.... but now, now it feels like my life is moving faster and I can make more decisions, even my family is helping plan things for my graduation and wedding..... idk if anyone else has gotten married right out of high school or if the turning 18 made a difference in others lives...I already have 1 job and pay my own phone bill and am looking for another job... I just need some reassurance that I'm not still a kid and I'm making the right choices in these areas... any help ladies?