I need help

So there’s this guy, he goes to my school, he turns 18 in two weeks, in 16, he asked me to prom, I said yes at the time, he seems sweet but now I’m starting to think that maybe this is moving a little too fast, just like my last relationship, he apparently is gonna ask me out tomorrow now I’m second guessing everything and I’m tweaking, am I a dick? What do I do??