Simple response
I'm prior enlisted, getting commissioned soon and heading down this path, and from my 7 years of experience of jumping through hoops(Aircrew school, SAR school, SERE, "A" school, FRS, NSI, NROTC, and everything in between), no school in the Navy is difficult to get through. Sure you have to work hard, but the only reasons I've seen people attrite are due to either medical, being as sharp as a marble, or most commonly, they quit due to a lack of mental strength because they are too worried. Oh yeah, and back to dumb, they get a DUI or do something else stupid.
Every school tells you their going to feed you information with a firehouse and on and on and on and as long as you are somewhat inteligent, you will pass. I had 2 pilots in my squadron, in the FLEET, get booted after about a year because they literally could not land the helo without slamming into the ground, and none of the crewman wanted to fly with them. So if they made it through training without proving that they could even land the damn thing, then you have no need to worry, unless your a moron.