Really, your question is monetary benefits. If you go to a private school, or very expensive public school (ex: out of state tuition), a 4-year NROTC scholarship will win out. If you go to an instate public school, biting the bullet for the first approx. two years and applying for NUPOC will probably be the smarter choice (it worked that way for me, though college was cheaper "back then").
NROTC will give you a shot at any of the line officer jobs. NUPOC will only give you a shot at the nuclear jobs.
NROTC will probably give you the chance to visit a submarine and go underway for at least a day. NUPOC will fly you out to a submarine in port and let you walk around.
So you've got a 4.9 GPA right now, and that'll get you into NROTC. What if you screw around your freshman and sophomore year? Stay above 2.5 and you'll probably keep your NROTC scholarship and have a job waiting for you, nuclear or otherwise. Wait for NUPOC and screw around, and you might not get an interview... And there's the matter of OCS after college.
Gamecock is right, probably taking the scholarship now is the smart choice. Complete your freshman year, keep your nose clean, PT, and make good grades, and then go to summer cruise. After summer cruise, decide if ship life is or isn't for you. If you do those things, then decide its not, the CO's endorsement on your DOR will probably still say "Recommended for future officer programs."
As far as maturity, you've got four years to work on it before it affects the enlisted, and if you're still not mature, they won't listen to you anyway.
Any questions, PM me.