So me and 6 other people got drunk and we are all 14. One girl offered to perform oral sex during this and I allowed it. Then the next day she was saying that I took advantage of her and she might go to the police. What could happen to me?
Ok, if you raped or sexually assaulted her, you could get in big trouble. But it would be her word against yours and the fact that you are both minors and were drinking would tend to muddle the whole situation. If she makes that claim, just the process could be real unpleasant for you, though, even if you don't get convicted.
If it's all consensual, you almost certainly won't have anything to worry about. There might be a low-level misdemeanor but in most states, sex between 14-year-olds is not something that gets punished severely. (Sex between a 14-year-old and an 18-year-old would be a whole other ball game). Oh and by the way, sexual acts involve two people, so if you get punished for receiving oral sex from her, she would face the same charge for giving oral sex to you. If anything, you are the passive participant and she is the active one so she'd have more to lose.
I think you should take this as that she regrets having oral sex with you, and might be trying to repair her reputation.