I’m all for closing the age gap. My husband is only a few months older than me, and we do just fine. Also, we got married at 20, which is normal for girls but on the young side for guys, so it raised a few eyebrows from his side, but b’h it all worked out b/c he was ready to marry at that time.
But you still have the maturity problem to contend with for 98% of the guys (assuming you don’t want to make the girls wait; not to mention too many of the girls these days also aren’t really mature enough to marry as young as they do). There’s no quick fix for that; the only solution to the maturity problem is to treat our children like we expect them to marry in their late teens/very early twenties. If you want them to be ready in time for that ‘deadline’, then please make sure they can cook, clean, balance a checkbook, etc and, most importantly, compromise and deal maturely with not always getting their way, by the time they graduate high school.