strange gender question

I made friends with this girl when I went out one night. We linked up on fb, then I noticed her posts that keep popping up. I think shes MTF, Ive seen her only appearing as a woman face to face. Which is why i say "her". but on current fb posts she presents as a man. So, if i were to see her for lunch and she were dressed as a man, would i use male pronouns? do i adjust the pronouns based off her attire/makeup/hair? also....are ppl who dress apearing as a woman ONLY when they go out on weekends considered drag or can they also be trans? im trying to educate myself so that i can avoid being rude. ******Thanks you guys. Im not sure Im comfortable asking someone their gender, it seems insulting. but, i will def avoid pronouns till they lmk.