IBS is not only about physical issues, but also mental. I'm not saying we are crazy, but the physical problems sometimes convert to overthinking. She might be a bit shy, but I have the feeling she thinks about the ibs-issue while dating with you a lot. You are telling you guys had a couple of dates and that she enjoys them. That's a very good sign and you should not worry about her liking you etc.
Thing is, it 's embarassing to explain everything to someone you are dating for example. You don't know what their reaction might be, and you are afraid it could be a turnoff for her/him and end it. Maybe my own experiences will give you some insight.
I think I told my girlfriend about my ibs on the 5th date. I'm very good at hiding my ibs, so she didn't noticed any weird behaviour at first. I was constantly pondering about things like : "Would she still like me if I will explain all my issues? Maybe she thinks I'm weird/weak/gross if I tell her? Would she understand? Oh man, I'm very afraid for the moment I will have to go 10+ min to the toilet at her place. What if I shit my pants, that will be awkward because she doesn't know about my condition?"
I was making myself crazy with all these thoughts, in hindsight it was completely unneccesary. Sometimes I thought about stopping dating with her, but you still want to live your life, so big dilemma. You want to be polite, so you go to places and do things you absolutely don't want to do with ibs. Because it's so hard to explain (and because it's a lot to explain as well) you don't tell the whole story at once. Maybe she is battling in her head about things like these as well, which is confusing for you.
Ibs comes with farts, noises, smells, 5+ number 2's a day, sudden-diarrhea, pain while sex and a lot more. Very embarassing, especially for a lady. It takes time for her to explain everything to you and be comfortable enough to cope with the ibs-issues while being with you. Maybe you should find a good place to talk and tell her she doesn't have to be embarassed about it. That you know she can be gassy and poopy a lot, but you are confused about what it really is like. That you want to understand her, what her ibs-problems are. What she likes to do without having to think about ibs too much. Ask her to cook together and that she will choose the recipe. Go through the fodmap lists together and buy groceries together afterwards. You get to know more about her diet while doing something together. Don't push it with questions though, but try to get her out of her shell by herself. Tell her that you are open to talk about every bit of her ibs-condition, just make her comfortable enough to talk about it with you. Communication is the word;) You are a great and good guy to start looking for info here because you care about her. But in the end you've to ask her about the info;)
Wish you the best and I hope it will turn into something great!