I would wager that Navy would offer you the best chance at obtaining a pilot slot.
There are no UAVs in the Navy.
Service selection through Navy ROTC / Naval Academy is limited to unrestricted line officer communities - so your choices are limited to : Surface / Submarines / Aviation / SEAL / EOD and Marine Corps.
You cannot go into JAG Corps / Supply / Medical / Dental / Nurse Corps or any staff corps or restricted line communities - no finance officer, no postal officer, no missile silo officer, etc.
Since the Submarine / SEAL and EOD communities are small, most commissions go into Surface and Naval Aviation, with number of Naval Aviation graduates larger than the number of Surface graduates. I would guess about 50% of each years commissioning officers from the Naval Academy and NROTC that choose Navy (instead of Marine Corps) track into Naval Aviation.
Since you are a senior, you are actually too late to apply for a 4-year scholarship for Naval ROTC or application into the Naval Academy for next year.
The process begins the spring semester of the junior year in high school, and scholarships are awarded the fall semester of your senior year, ending around the winter break.
You need to start working the nomination process with your congressmen if you want to attend a service academy (Air Force/ Navy / Coast Guard or otherwise) or service academy prep school.
If you decide to go the ROTC route, you can walk on as a civilian and attempt to compete for the 3-year or 2-year scholarship. There is no guarantee of which community you will track into and you don't get to choose until your senior year, so Naval Aviation is not guaranteed, but it's 50% of the commissioning class.
With Naval ROTC, you incur an 8-year service obligation as soon as you start your sophomore year with a scholarship, or junior year as a non-scholarship student. If you don't complete college and commission as an officer, your 8-year obligation is served as an enlisted sailor.
Otherwise if you still want to become a military pilot, there's always the Air National Guard. - you still need to get your college degree and you have to hunt for a Guard unit that will sponsor you for flight training.
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.