18 and about to have my first kiss soon 😩

I'm so nervous about it. I've turned my boyfriend down about 5 times now and I really want to kiss him I just don't know what to do with my lips!! Every time I think I'm ready to kiss him and he leans in, I panic because I really don't know what to do with my lips. Can I have some pointers?? It just doesn't make sense to me and I really don't wanna be bad ):