Allow me to draw another Harry Potter-parallel (although Star Wars and Harry Potter should probably be kept seperate). Even after seeing the damage Voldemort had caused, Dumbledore allowed him to go the Hogwarts. The kid was a bully, but he was probably among the most powerful potential wizards Dumbledore had seen. IMO, Anakin using the Force accidentally would not ruin him being the Chosen One. It shows that he has great powers, but that he has not yet learned to control them. It would not be because he meant to do it - he should probably be as baffled as the crowd - more like a reflex, like InfoDroid said. So he would not have learned to use the Force at this point, but he has the abilities.