I took a different approach. As a kid, and now, I was nuts about being over, on, in, and under the water on anything that would float (and sometimes not).
I went to school, earned an Electrical Engineering degree and pursued anything on the water. Since then, I've logged 15,000 sea miles, mostly on Navy destroyers and cruisers as a civilian contractor. I love my job and wouldn't trade it for the world. But my observation as a lifelong sailor is that the current Navy is woefully unaware
of the sea. They have virtually no feel for the water, their line handling is poor, and you may find one person on a ship that can tie a basic french spiral (woo hoo). Commercial vessels do not hold their Navy brethern's skills in high regard for a variety of valid reasons. The Navy runs ships like a bus line with firm departure and arrival dates plowing through whatever gets in the way. In other words, they're power-boaters.
There are virtually no jobs in the Navy that will prepare you for living aboard a boat (living on a destroyer is no way
like living on a boat - I know). Of necessity, the Navy is all about data, computers, and weaponry. That's what they do; the sea is road upon which they travel to whatever mission they are assigned. My suggestion is to enlist, go to school, learn a job that is marketable (I'd add Fire-controlman, Radar Technician, Cryptologic tech), get out, and buy a boat that you can afford to sail. The glamor of living on a boat for pennies is a myth unless you live on a wreck (San Diego Harbor and Ala Moana Harbor in Honolulu are full of them). Even then, slip rental is still expensive.
Use the military to get an education and be proud of your service in the meantime.
Understand that I love and have high regard for the Navy, their technical ability, and ethos. But the days of rugged seamen with seaweed in their teeth are over. These are impressions of a life on the water and just my $0.02 'cause you asked.
PS. I just realized that 75% of the crew in my avatar followed the path I prescribed above. Most own their own boats or crew on others.