Look, both of you are likely very inexperienced and have super high expectations about what sex should be. This would make anybody nervous, I like the suggestion someone made below about spending time together naked without sex, just getting used to the idea of being vulnerable and curious around each other.

Your girlfriend may be just as anxious as you are. It's very likely that what she does to you may not feel as good as your hand, and vice versa. How would it? Neither of you know what the other one likes and how they like it.

Talk about it, make it something fun. Sex is meant to be fun rather than a chore or a negative experience.

How anxious do you feel about having sex? Do you think this is some sex performance anxiety, insecurity, or something else making you worry obsessively about sex?

If your friends will slander or leave you because you decided to leave a relationship you are not happy with anymore, then those are not really your friends in the first place.

How could you give your own brother the Spicy Keychain, Dominic?