About half of each graduating class goes into aviation from USAFA every year. This year there were 240 midshipmen who got a Navy pilot slot and 105 who got a Marine Corps pilot slot.
It also depends what you want to fly. Fighter Jets? Helicopters? The Air Force has more options but both will be difficult to obtain a fighter slot.
You also have to take into consideration that you might not get a pilot slot at all and it depends on what you would want to do as a backup plan. There are some instances where cadets were medically disqualified from flying and couldn’t pursue aviation as a career. If something were to go wrong would you rather be in the Air Force or Navy?
Best of luck to you and hopefully you get into both!