Joe, I agree with Cuculeis. Talk to a recruiter for the specifics. The thing about Navy OCS is that when you apply you can select up to three choices to be considered for. It's not like the Army where you list choices and after OCS you can be picked up by any MOS even if you didn't list it as one of your choices (major drawback to Army OCS in my opinion). With the Navy, if all you want is pilot, you would list that as your first and only choice. If you are accepted then you are guaranteed that designator. You won't graduate from OCS to find out you've been reassigned. Of course there is the posibility that you could find yourself medically disqualified at some point prior to, durring, or after OCS. In this case you can request a transfere to another designator or take a medical discharge. Also-- at 28 I think you'd be able to get an age waiver. But I wouldn't waist time-- talk to an officer recruiter as soon as possible; the application process can take a while. For some people it goes pretty fast and for others it is very slow. For me is been the later. Just depends on your circumstances I guess. But to be on the safe side, don't waist time-- birthdays have a way of creeping up on you.
Best of luck...
Chris