Glad we had our DCs at 26 and 28. We're now about to get into our 40s and life is good.
We were lucky, had plentiful babysitters, so we still met up with out childless friends as much as we could when they were small. Now many of those couples have babies / toddlers and it's nice to be out the other side, as it were.
We have still kept up our careers, but have just had to do it with the kids as well. Glad we didn't wait, I'm excited for our late 40s when the kids are grown and we have plans to travel (with them too if they'd like, depending on where we go and how long).
We had to really put in the effort to keep up with our friends in our 20s though, or we could have drifted apart with us being young(ish) newlywed parents and them child free (As I say, very lucky our parents could/would have them for sleepovers fairly regularly when they were small, and now. They also used to look after them whilst we were working).
They're now in their late 60s/70s and there's no way they could do as much now with regards childcare. So I guess that's another bonus to having kids on the younger side.
So maybe I should give a shout out to the GPs here!
(Sorry, its a ramble, having a NY's day wine in the bath and can't be bothered to edit to be more succinct!)