Boebert would be shocked: "your 30's is when you become grandparents!". Anyways...

I was checking some complementary data about marriages and it seems like the age is about the same as the 1st child which sounds logical.

I wonder if that means longer marriage. I'd expect that because it's supposed to be a more matured decision and people tend to change less after a while. You know yourself better in your 30's than in your 20's...