Alright so here is my situation. I met this chick at a bar (I'm 22 and shes 27). We make about the same amount of money. I have not done a great job establishing a dominant masculine frame from the get go, and I take responsibility for that. I cold approached her the night I met her, and ended up buying her a drink. The second date we payed separately. The third date I paid and she didn't attempt to split the bill. She did, however buy one round of drinks on the most recent date, but then made a comment in a joking tone about how I will have to pay from now on. We haven't fucked yet either.
tl;dr: How do I bring up the topic of who pays when I have already fallen into setting the expectation that I will pay? I don't want to come off as a dick and make a big deal out of it, but how do I reset the perspective appropriately?