I'm not sure what to do 😞

I like this guy but he's 4 years older than me.... he's super hot and knows he his too. I had sex with him right away which I feel like shit for doing but I felt comfortable enough at the moment. I'm scared I'm falling for him and I'm not gonna be second best.  I NEED SOME HELP!!! 
I'm 18 
Let me clarify a little more! Sorry! 
He's older than me he has a lot going for him I just don't want to get my heart broken in the end. I've been spending a lot of time with him and we are family friendsÂ