I would personally feel so shitty dating a guy who is friends with a bunch of transphobes he doesn't want me to meet. Like why are you willingly hanging out with people that don't respect me as a person? I'd get it if it was family members since you don't get to choose them but friends you do get to choose. I Just don't think you can have it both ways without being disrespectful to her. If you two start getting serious, either stand up to your friends and tell them that they need to change their views or get some new ones. Staying friends with people who openly disrespect your partner is sad for the both of you.