My ex MIL has body shamed me and my kids: Advice?

My ex MIL keeps making comments about her grandchildren. I am African American, my kid’s father is White. Therefore, my kids have a tan complexion that is a mix of us both. When summer arrives, black people turn a 4- 5 shades darker. This means the same for my children. When we swim or go to the lake my kids come home a completely different color, and my daughter gets just as dark as me. (Mom). My issue is with my ex MIL- son and i are not together but still close enough with his family to co parent. No family of my own. Here…MIL makes the most inappropriate comments about my daughter, " Wow you’re getting too dark" or “Girl if you get any darker. No more pool for you lol” right in front of me…I don’t like it and neither does my 5yo daughter. The other day she told me she wish she was white- my feelings are hurt because she is litterally the best of both worlds.I haven’t mentioned it to dad, idk of he’ll understand…He told my son once that he and his sister are "basically white"I feel the need to speak up because in the past she has said things that should not be said …She’s body shamed me and recently my son for being small and petite, I finally spoke up and she’s never done it again.Her excuse was that she’s jealous of my body- buy that does not make it okay to shame ANYONE She shamed her 8yo grand daughter for being fat and eating too much & for having curly hair that her mom CAN’T maintain… she says curly hair looks like rats nest. MY ex sister said something and it never happened again. Idk If I’m going to rub anyone the wrong way when do mention something. But I definitely will be saying something.Am I over reacting?? Put yourselves in my shoes