If you're really worried about it, I'd say it'd be good to find an autism center and have him evaluated.
It doesn't sound like Aspergers to me...possibly ADHD?
I don't know if everything is "normal." But I do want to tell you that everything is okay. Even if your 3 year old has something that is different about him, he is who he is supposed to be, and everything will be okay. Yes, he might have struggles later if there is something different going on, but, totally nothing that he and you can't handle.
I would suggest having him evaluated. If there's something different going on with him, it's better to know sooner than later.