Most women like that part of getting married. They get excited about it. They want their kids to have the same last name as both parents and they want to share the name of their husband. Please try to not turn it into some male domination thing, as so many discussions on here needlessly turn to that. It's like the HN version of "all discussions eventually lead to Hitler," or however that goes.
My wife was 18 when we got married. She wasn't "well known". She wasn't a feminist. But she kept her last name and it has never been a problem - except for PayPal.
Our kids have her last name as their middle name and my last name as their last name for convenience - mainly the school's convenience.
Personally I hope some day we go to a system where you turn 18 and pick the name you want. I've known at least two couples where when they got married they didn't choose either name, but took a name for "them". I personally would like to see more of this, but then I'm a bit of a romantic.
o_O
Many early marriages fail (but then again so do many late ones, so that generalism might be based on confirmation bias) but some people are mature enough to have a solid relationship and life plan by that point so getting married early works for them.
I simply wish we didn't feel like we have to excuse women keeping their own name, and hope that one day it will simply be the default.