Dealing with gf's ex

Okay so pretty much, my girlfriend told me she still has feelings for her ex. Not sure if I should just break it off or try and fix this shit. I'm in highschool so really I don't think relationships are going anywhere. And I'm beginning to think she's just a normal highschool girl who can't seem to get through her head It's fucking highschool. So any advice on what to do is helpful, either stay and deal with this ex shit, get laid and break it off (alpha option), or just break it off now before all the drama. Btw its been almost a month we've been "dating." So tell me reddit what would you do in my place? Also any story of crazy bitches acceptble and also thanks for reading.