First off, (not trying to be rude), but shouldn't you have looked into all this BEFORE getting a puppy?
That being said, heelers are very active dogs. They are a herding dog, so of course they are going to be very active dogs. They can get aggressive, so just make sure you socialize you pup well with strangers, kids, and other dogs.
Well bred working pups will show an early biting/nipping....so make sure you cure that if it happens. I have worked with and trained quite a few heelers for people. They are great for working livestock that will try "run them over" so to speak b/c they have a great deal of determination. My good friend has a 7 m onth old blue heeler pup that already works his bucking bulls. And, let me tell you what....bucking bred bulls are NOT a nice thing to try and move/mess with. If that pup gets kicked/hurt, he just digs in harder. It's amazing the determination that he has at such a young age. They also get angry easily when it comes to stock. I wouldn't recommend them for "fragile" livestock.
Anyways, have fun with your pup. Socialize him and obedience train him and he'll make a wonderful pet.