There are 2 considerations. One is biological. Women fertility drastically decreases after 30. And also increases complicacy during pregnancy .
But other is maturity. Many people who are getting married at young age like 22-23 are getting divorced at much higher rate. They later feel like they lost their youth and then have mid life crisis at 30. Especially when wife is stay at home and kids start to go to school.
Also if you're doing love marriage, you also look at can the relationship survive long distance and will your partner be a good roommate.