Should i take her back?

My gf and I broke up at the time she said it was because she thought we werent compatible but we've still been talking kinda and she just told me what happened was that she got drunk at a party amd gave a guy a hand job she said he broke up was because she didn't want to tell me but she didn't think that she should stay with me because I deserved better than her for what she did but now she's telling me it was a mistake and she wants to be with me and what not. What should I do ? She's an amazing person and I like her a lot but idk