online relationships never work out, believe me. But real life relationships dont work out most of the time either, so whatever.
Like other people suggested, cam, lots of pictures. But some ppl dont have cam, some dont take a lot of pictures (like me). Ask for his phone number. u guys can talk on phone. U can tell by the voice how old he is (mostly). Call using your landline (with the excuse that your cell is dead) and see what happens.
But what can an online predator do to u >.< just make sure u dont take nude pictures and send to him, that's all. He probably wont rape u, since no one ever gets away with it in US.