How would you feel

My son and his wife met when he was 16 and now aged 42 and 22 years of marriage and 4 children later, they have split up. He says it's something they both want and so far it seems amicable. Only a month later he's met someone new. I've met her by chance on two occasions and she seems lovely, but she's only 24 -just 3 years older than his eldest son. I'm in a quandry here, as she seems like someone I could really get along with, but I can see trouble ahead when his children find out. On the one hand she seems good for him and I'm happy that he's happy, On the other hand I think she's far too young and it's far too soon to be embarking on a new relationship and then there's the children to consider. It's no wonder I don't sleep at night!