Is this normal for a 9 y/o girl?

I’m still trying to mentally understand my 9 y/o daughter. The other day, my wife commented that it seemed our daughter cut her own hair. I said I knew nothing about it, and it seemed fine to me, because it did.

Today, in one of the bathroom trash cans, I found a large clump of my 9 y/o’s hair. I was dumbfounded. It was with a hair tie. I asked my daughter about it immediately.

Her answer was: She couldn’t get the hair tie out of her pony tail, and because my wife and I were taking the trash out (we were gone for five minutes), she cut it out herself.

She could have waited. I don’t get it. Why?