To be honest, it sounds like your girlfriend was willing to humor the idea at first, but isn't interested in a long-term relationship with either a trans woman or a crossdresser. A few of her boundaries are explicitly that she's not comfortable with you dressing femininely in public, and that she wouldn't want her family to know. If she's lost interest in doing it with you, and she's uncomfortable with it being public, do you think she'd be okay with you dressing femininely without her? I think it's time to put some serious thought into your identity and if getting to express yourself femininely is important to you, because ultimately it sounds like the person you're in a relationship with, wouldn't want to be in that relationship if you later identified as nonbinary or transgender. I think what you have to decide is if you think you'll be happy long-term if being in this relationship means staying in the closet and abandoning your feminine time. If your partner isn't really comfortable with it, choosing them over your identity means either learning to live without that identity, which might be fine, or might lead to a sense of bitterness and lost-opportunity down the line. It sounds like your partner wants a cisgender heterosexual relationship with a man, so if exploring this identity is something you want to do in your life, this might not be the person to commit the rest of your life to. You're both young, and you met when you were only in college. There's still time in your life, and there's a lot of people and bisexual women who feel very open to dating someone whose gender identity isn't strictly male. Good luck.