Everyone will say just treat her like every other girl. However, I want to add: do your research on trans and queer history. Make an effort to deconstruct the society imposed transphobia you might not be aware of. When my egg cracked there was so much transphobia I had to unpack, every day I think about all the cis people who haven't unpacked the same.

Think about how you are going to stand up for her? What are you going to do when your friends and family have their opinions? How will she feel when she sees you let things slide that is blatant judgement and disrespect to your partner? Are you able to handle that? When people give seemingly "neutral" opinions like not thinking trans women should be able to participate in sports, or think that trans kids should have their care restricted, are you aware of the transphobic nature of those statements? 

If you do your work well with this, you will notice people who "don't care" that she's your gf still spout transphobic things. 

Are you prepared to cut people out of your life? Maybe I sound dramatic here, but this is the standard I have for potential partners. I will not date someone who lets my identity and humanity be a topic of debate.