Losing it. BUT imma little worried, but I wanna, but how?

Okay, so there's this guy (isn't that how it always goes) and he means a lot to me. Now, I'm a very sentimental gal and both of us are virgins so I want to have sex, but I'm literally freaking out because I THINK WAY TOO MUCH. Even to the point where I'm thinking myself out of feeling pleasure, if that makes any sense at all, but I want it to be enjoyable. How can I initiate something like that? UGH help. Tips? Moves? Help? Anything? Hell, I don't know.