Minimum Requirements
In short, yes. It's well over the requirements to run it.
Your only possible problem is going to be the screen resolution. Netbooks have a special-sized screen that uses a different resolution than standard notebooks. Stepmania might stretch to fit the screen, I'm not sure, but I can guess it does not have a compatible resolution with netbooks. It stretching the screen could cause video lag here and there and will likely make the arrows look either too wide or too thin, but all in all you should be able to play it.
I would recommend just buying a real laptop though, you can get a pretty decent one for about 100-150 more than a netbook and you'll be a lot happier in the long run.