ITS A LOVE STORY, BUT SHOULD I SAY YES?

please read: so i've liked this guy for probably two years. We've dated, broken up, hooked up, you name it. Were always on and off and after growing up and apart a little we decided to give it another chance. We know that we want to be together and some point and we can't picture each other with someone else. but sometimes i feel like hes not mature enough for a relationship. and i am known to be a really flirty fun girl--and i know getting into a relationship will result in sacrificing time with friends, hanging with different guys, and partying. I really like him...atleast i think i do. Please help im confused...