My U10 daughter plays a year up (U11 girls)- she is actually 9. I was told by her coach today that instead of training this week they will be playing a friendly against the U13 boys. He said there will be conditions on the game but in my opinion it would only take a small lapse in judgement to make a serious injury to one of the girls. 

I realise that children can play mixed up to U18 but this is a whole U13 boys team playing an U11 girls team that has some 9 year olds in it. Am I being over cautious?

TIA