The girl did something hurtful to her boyfriend, and wants him to know how much she regrets it. No clues are given as to exactly what she did, which I think was intentional, so the listener could base it on their own experiences.
He responds that, "mistakes are part of being young." I find this line out of place, because it's not really something a young person would say. It's something an older person, like a parent, would say to someone young. Just how old is this girl's boyfriend supposed to be? But, I don't really think that's what they were trying to imply. I think the line is just poorly thought-out.
The girl did something hurtful to her boyfriend, and wants him to know how much she regrets it. No clues are given as to exactly what she did, which I think was intentional, so the listener could base it on their own experiences.
He responds that, "mistakes are part of being young." I find this line out of place, because it's not really something a young person would say. It's something an older person, like a parent, would say to someone young. Just how old is this girl's boyfriend supposed to be? But, I don't really think that's what they were trying to imply. I think the line is just poorly thought-out.
[Edit: Edit]