I don't know why she keeps going to playgroup with just Mila? And she makes it all sound super important, like having to pay in advance, waiting lists. If only taking one Jace should be the priority and would really benefit from getting freedom to explore new toys/activities with other children a similar age. Where I go lots of people have more than one child, there are 3 and 4 year olds that go depending what days/times they are not in nursery, and you only pay when you go, per adult so wouldn't cost any extra to take both children.