You can start BMX on any bike. But once you start trying spins and what not, the peddle brake will make things rough. You see, in order to do a 180, you must roll backwards for a period of time, and this wouldn't allow you to do so. But if you're just starting, go ahead and learn how to bunny hop and hit jumps on that bike. If you keep going with it and enjoy it, look into getting a real BMX bike, not just a walmart bike. You don't need to spend thousands of dollars, although you could end up doing so. Just a nice starter bike. Chromoly frames are ideal to hold up through the beating you'll put on it. If you need more help, just lemme know.