Is it weird that i don't hold a grudge, given the circumstances?

A bit of backstory.

When I got to high school, I was immediately one of the popular kids, and I definitely let it go to my head. I'm ashamed to admit it now, but as the years went by, I became a total mean girl. By my junior year, I thought I could do anything I wanted and treat people however I wanted and get away with it because, for the most part, I did.

Then I made the move that caused karma to kick me in the ass, hard.

I went out with a friend's boyfriend behind her back. At the time, I thought he was really cute and he was definitely into me. So I made a move and he went for it. When my friend found out, she was livid, of course. She and two of her friends confronted me when I was in the bathroom one day and she attacked me. She threw the first punch, but I threw the one that ended the fight. I actually broke her nose.

The three of them lied to the administration and said I'd started the fight. The principal called the cops and I was arrested. Some months down the road, I was found guilty in juvenile court as all three of them stuck to their story. The judge, sensing (correctly) that I wasn't feeling any remorse, opted to give me the toughest sentence he could given my offense. He sentenced me to six months in juvenile detention.

I can still remember being lead away from court in handcuffs. And seeing my three ex-friends watching. They looked like they were trying not to laugh.

When I arrived at juvie, I was really pissed off about my situation. But as time wore on and I had plenty of time to think, I began to feel genuine remorse. I began to see what a colossal bitch I'd become and how really I was only getting my comeuppance. The three of them may have lied about who started the fight, but that didn't mean I was innocent.

I got my GED while in juvie. After I was released and after spending a year at community college, I transferred to a four-year school. I'm now twenty years old.

Earlier in the year, I saw the girl I punched for the first time since court. Turns out we're attending the same college. We spotted each other from across the cafeteria and made eye contact. I could tell from the look on her face she didn't want to talk. I gave her a nod and a smile, which I could tell confused her.

The way I look at it, she did me a favor by lying and getting me sent to juvie. It forced me to take a hard look at who I was and realize that's not who I want to be. In the end, she helped me to become a better person.

I relayed all this to my roommate recently, who couldn't understand why I don't hold a grudge against her. Is it really that weird that I don't? What do you think?