Why would they be immature? Unless you befriend 16-year olds, grown women wouldn’t be immature just because they are younger. My daughter is in mid 30s. Not immature.

As about busy with families. Many women don’t have children or welcome an opportunity of taking time off family and going out. Also some older women are even more busy. A friend of mine has 5 grandkids, she’s in her 60s but is busier than anyone because she has something going on every weekend. Even exponentially speaking, one might have 2 kids but 6 grandkids and if they all live close by, forget it. You’ll be busy.

Generally speaking younger women might have more desire to drive further snd in the dark and party more and possibly do more adventurous things (unless they have toddlers at home).

You also might want to look for single women. It doesn’t mean they are free 24/7 as they likely work snd have obligations and hobbies etc but they still might have a bit more free time. You want to see friends more often. So that’s might be the answer