Hands down ... If you want a guaranteed path to Marine Corp Officer ranks: Take NAPS!
There is not only no guarantee of NROTC scholarship if you enroll at as a College Applicant at your chosen university, there is also no guarantee of Advanced Standing either. It is quite possible (particularly in the current military draw-down environment) that, after two years of working your tail off with your NROTC unit, that you'll be told you must leave the unit. The particularly distressing part is that the final decision with Advanced Standing does not rest with your local commanders. They can try to influence the decision, but that's about it.
NAPS, on the other hand, only requires you to meet the minimum requirements of the NAPS program for 1 year. Do that and you are virtually assured into the USNA Class of 2019 -- and a clear path to your goal to become an officer. As far as the extra year goes, I'd point out that you'll likely look back on that year of prep as a really good thing. My son, who has been accepted into the USNA c/o 2018 this year, just spent a year as an NROTC College Applicant at a state university. His take (which I believe to be a good one) is that this past year has allowed him to mature and better prepare for the rigors of the Academy. He's glad it worked out the way it has (even though the stress of two years of applications was tough). I've heard similar stories many times from others. The college and NAPS plebes seem to, as a general rule, have an easier time adjusting to life on the yard.
Congratulations on the NAPS appointment!