I don't think anyone can give you a true answer because realistically you are talking about 6 yrs away for OCS on a good day. There is too much upheaval in the military right now for anyone to plan that far ahead.
Had it been 5 yrs ago, I am sure people would say the chances are strong, but now after seeing fewer scholarships going out people are seeing that nothing stays the same.
It really has to come down to what their manpower need will be in 2018 and that is because OCS will increase or decrease depending on the amount of commissions coming out of USNA and NROTC.
The best any advice anyone here can offer you is this:
Make sure in HS you are competitive for USNA or NROTC scholarship so that OCS will not become your Plan C.
That means you are taking the most rigorous course load you can handle, you have EC's, hopefully some sports, and can do well on the CFA/PFA.
Also, the one issue that kids your age tend to not pay attention to is medical. They do not realize that although they have what they deem as a minor health issue, i.e .never kept them from playing sports, it can be deemed as a medical DQ. Sometimes these issues can receive a waiver, but it is best if you know of it now to get it taken care of. For example, certain prescribed meds can cause a DQ, because you have not been off them long enough, yet the candidate never knew that this med would cause an automatic DQ.
You are doing a great job by being in front of this so early, and realizing you need back up plans, now it is time just to do great in school so you can choose which plan you want to select.