I agree to a degree on the first statement as me and my fiancee (both in our early 40s) still act a little immature at times yet when we have to we "adult".
Agreed, plenty of time to have a family if ultimately you want one.
I've had a few relationships that didn't work, the hardest breakup was one when I was fresh out of college as still had a wandering eye but eh in the end the one I eyed I ended having a longer friendship than had the one relationship with. Yet now in a lasting relationship with someone different and have no complaints.