Having sex for the first time (with a guy)

So I’ve only been intimate with women because of some experiences that have caused me to lack trust in men and I’ve pushed any and all possible feelings for men I might have had away. I’ve only dated girls and I’ve identified as a lesbian growing up. I’m in my second year of college now and I’ve been thinking of having sex with a guy. I’ve been having these thoughts for almost a year but every time I do, something happens that makes me ignore it. Trust is such a big thing for me in bed. Especially with guys. I was talking to one of my closest male friends about this and one thing led to another and we have been messing around lately but we haven’t gone all the way. He’s so patient and gentle and he won’t take steps without asking if it’s okay. And I trust him completely. I want to do this with him but I don’t know what to expect or how to even touch him. I also can’t help but think I might panic in the moment and I don’t know how to calm myself down if that did happen. Im hoping for any kind of advice.