Do you feel that they are judging you for being straight? I think you need to understand the root of your discomfort. These are issues you need to figure out on your own but use your time spent with her to help you figure them out. Try to find common ground with her and her lesbian friends that do not have to do with their sexual orientation. For instance, talk about your pets or hobbies or favorite movies and TV shows. If they mention things that you are unaware of, for instance, the TV show, "The L Word" then you can ask them about the show and use that as an opportunity to learn more about their culture. It's great to be around people who are different from you, it gives you an opportunity to learn! Embrace it and come out more aware and more knowledgeable than you had been before.
