You had a moment. You picked your poison. You can’t change that. You need to understand that… and she needs to accept that.

If you guys want to be together, then try it.

Tell her, and explain it. You screwed up big time.

If it were me I’d ask if you guys could at least take everything step by step and day by day. And, if I’m the end she can’t forgive you then it’s best you two separate. Neither of you need to be miserable at such a young age.