DH and I got engaged at 21 right before senior year. We graduated (at 22), got jobs and got married at 23...had our DS soon after (was not the plan, but it worked out just fine). My DH passed all the actuarial exams and is a fellow actuary (FSA). I have a bachelors in Sociology. We have been married for 16 years and have 3 kids. We were the rarity though.
My 2 best friends from HS did not go to college and got married to their HS boyfriends around 22-25 as well. They are also still married.
My DH's friends all got married later (closer to 28-30) and had kids later...when we go to parties with them all the kids are toddler-elementary aged while ours are teens...we have it easier and can sit and enjoy the party while DH's friends are still chasing after little ones (some are still changing diapers).
My sis-in-law married her HS boyfriend around 23 too, but both of them went to and graduated from college 1st...he owns his own business and is doing very well, so well that my SIL could quit teaching a year and a half ago. They have been married for about 21 years.
It's probably the same now as it was 16 years ago and most folks get married around 25-30. I am glad we did it young and had the kids young...we were all done at 25 and I had the energy to keep up with them and could easily deal with lack of sleep too...I don't have that now at 39. And now, DH and I can have date nights and go wherever we're invited as our kids can stay home alone. We can do short trips with just the 2 of us (though DH doesn't like to...he feels too guilty since the kids will be leaving us all too soon, he wants as much family time as he can get now).