The Shulchan Aruch says boys should get married at age 18 (no later than 20)
“how much more mature and ready for marriage will another yr or two in beis medrash make a bachur”- maturity doesn’t necessarily come with age, it comes with responsibility. I know plenty of 30 and 40 yr olds who are on the maturity level of 10 yr olds.
I dont believe the 2 more years in beis medrash will make bachurim into better husbands.
Get married young! (its more complicated once once ur older)