Look girlfriend seems liberal enough (gays, trans, slavery...).
The real question lies in her family/community.
Are they liberal?
Is she open with them? Do her parents know she is dating you?
Is she close with her community?
There is an old saying that is always true. You don't just marry the girl. You marry the family. And if she's still the kind of girl that hides thing from her parents, wants to please them, doesn't want to shame them... then you have to take that into account.
To put into perspective. Your very existence is a shame to her family.
A lot of this depends on your personality as well. Because you becoming Muslim doesn't just end with a marriage ceremony. Every decision you make in the future with your wife will be framed by Islam as well. What will her parents think? What will happen if people see this or that? Just keep that in mind.
It is perhaps easy for your spouse to just say go along with it. It is perhaps easy for you to think you can just go along with it. But neither of you has done this before. So all I can say is tread carefully. Everyone wants their cake and to eat it too.
She wants to be the good daughter to her family and community.
She wants to be good to herself and her views. Probably why she is not dating/marrying a Muslim man who would actually be acceptable to her family.
She wants to be good to you and make sure you are happy.
There's a lot of conflict here. I don't blame your wife. She is looking to get the best deal she can out there. Most of us are. She likes your liberal self and how non-oppressive you are. Great, all the benefits of marrying a modern secular person. But she still wants to be the good Muslim girl to her family/community. So she wants to do that too.
Let me ask you this, since you seem like a modern guy against the patriarchy?
Would you let a man get away with this level of hypocrisy, opportunism, and cowardice?
If not, why are you placating it to her?
Or do you think it is your job as a man to protect and sacrifice for her, because she is a woman? Ponder that a bit. I was in a similar position and see the contradiction a bit more clearly now.
Here's my concluding remarks. Take it for what it is.
She is your wife and she is supposed to be your top priority.
You are her husband and you are supposed to be her top priority.
By converting, she is placing her parents and community above you. That is an indication of where you stand in her life and the future it holds for you both. If she is not willing to take on her parents right now, she is not ready for marriage with you.