CMC may have selected you specifically because you wrote about kindness! This matters a lot at smaller schools with tight communities. Terrific school. Actually, a few years back, a friend’s D was rejected there (her first choice) and accepted to Stanford. She was as disappointed as you. It’s all a little random in terms of what each school is looking for.
I mention this because it may explain the results of the person you know who got into Brown. You also don’t know how she came across on paper.
But mostly, huge congratulations to you on what is sure to be an amazing experience at CMC. You sound like an incredible person who is bright, ambitious, and who cares about the people around them. That’s a recipe for success in life. Don’t sour it with regret!