My 16 year old girlfriend got drunk at a party and cheated on me?

ight me and this girl have liked each other for years.just never conected and started a relationship on my birthday (two weeks ago to this day) i have fallen head over heals for this girl because we have shared so much time togeather and have had many of the same problems.She told me today that she had gotten drunk at a party and had with another guy.i could tell that she was upset about it because she wanted us to work out, for so she told me.like i have said before i have like this girl for years and she says she liked me for years,since high school 3 years ago.do i try to work things out.if so any suggestions.or do you think that i should just move on and see if she can grown up into a good person with out me.there are so many questions running through my head.i feel like i have fallen so in love with this girl.i always want to be around her.but this is the first time i have been cheated on.we had every thing worked out between us and everything was great up till now.