^It's not so much that he's a perv, he's just very.... innocent, or naive, if you will. Again, think of Goku in early DB; he grew up in the mountains with just his grandfather, no other outside human contact, so he didn't know that women are.... built differently. This is pretty much the exact same case here, lol. BTW, apparently Elba gets shocked later on when she learns Percy's actual age (at 16, he's technically an adult despite his appearance!
).
And yes, that ending is quite curious, indeed. Definitely looking forward to seeing what his newfound powers are....