Have I maxed about the EVs (Pokemon)?

New to this... Have been using Macho Brace on a Rattata from Lvl 1. According to how I record the battles and the vitamins I've used on it, it should have almost 550 EVs. It's only Lvl 19 now though. Is this right? Isn't there a limit to the EVs it can get? If I have maxed the EVs out can I now feel free to fight any Pokemon with it normally withou worrying about getting the wrong EVs?