AITA for refusing to punish my daughter after she blew up on the classclown that she dint want at her birthday party?

My daughter is 12 and she goes to a small school. Her grade only has 18 students (10 boys and 8 girls). My daughter also has other friends from the sports she does. We plan to have her go to a much larger high school in the future. Her 13th birthday party was last weekend and I asked who she wanted to invite, she wanted to invite 7 of the girls from her class and 5 from her soccer team. The one girl she doesn't want to invite is name Kelly.

My daughter doesn't like Kelly, she is the class clown in her grade and my daughter hides her annoying and attention seeking. I asked her why she didn't want her there and her response was "she ruins school for me all the time, I don't want her to ruin my birthday." I agreed with her list and sent the invites out.

My ex-wife is invited to all her major milestone instead of us doing separate events. I learned an hour beofre the party my ex-wife sent an invte to Kelly since her mom found out about the party. My daughter was not happy to see her (it was a suprise for her), I told her to enjoy the party.

It was going well until the cake came out, my daughter wanted a glitter cake (when you blow out the candles glitter goes everywhere). While everyone was around the cake, Kelly took her fingers and swiped icing off the top layer of the cake. It ruined the cake and my daughter lost it. She yelled at Kelly, basically saying, " what is wrong with you, this is why I didn't want you her and that you ruin everything." She ran to her room after and Kelly was crying.

Kelly's parent is wanting an apolgy, my ex-wife wants her to apoligze as well. I am refusing to make her do that or punish her at all. I pointed out that my ex never should have invited her and to the mom that her child ruined the cake, and that at 12 years old should know better. They are calling me an ass and my daughter is just upset.,