help!!

ok so i’m 14 & i’m a freshman in highschool. I’ve been dating this guy for almost 4 months & we both really like eachother. & we’ve talked about me giving him head. but idk. he’s never had sex or done anything like that w anyone else but i’m scared he could have something & that I could get it. other than that I want to do that w him but if somehow I got something then my parents would know & that would be the end of me. idk what to do.