Its true some events are really PG and friend dates were common. I was in Greek life, don't let these people make you feel like your feelings are controlling or irrational though. I'm not going to try and scare you but I will tell you the reality of some of these chapters and their events. These kind of events have plenty of alcohol readily available. There are also usually pregame or after parties were things tend to get out of hand. I've seen 18 year old girls show up to events completely smashed and throwing up before the event is even half way through and I've seen guys trying to take advantage of them. It's scummy and disgusting but it happens. So make sure if you are going to be cool with this you know what her before and after plans are. She already kind of threw this at you, so is she not telling you about a before/after party? They're not official events, and are often held in a brothers apartment off campus but there is always one going on.

Next thing I would do is check into the chapter. Every school is different. At some schools pike has a lot of date rape cases and a shitty reputation, but at other schools they're the model fraternity. So maybe ask around about their reputation on that particular campus. Even then keep in mind there are always shitty people in even the best of chapters.

Finally there is the problem with her doing this to you. This is already a new relationship, there really isn't a solid foundation of trust here. For her to throw this at you and expect you to just be okay with it is not only rude and inconsiderate, it might be a red flag telling you she probably doesn't consider your feelings important. I'd be seriously reconsidering the relationship personally but that's just me