Trooper's mom

We just adopted a rescue dog and I believe that he is a JRT mix. The Jack Russel and Chiuaua mix looks like a good match for him. I would like to have more info to see how big he will get. The pound said he was about 8 weeks old, but he looks bigger than that. He has the face of a Jack Russel tan and white coat long skinny legs. He can get hyper when playing. Also when I walk in the room he gets excited, but he also loves to cuddle. As I said he's a rescue dog my friend is a foster parent for rescue dogs and she said he would be great for our family. We have been wanting a dog but was waiting for the right one to fit into our family. We have a 10 month old girl and live in a apt in the city so an extremely hyper territorial dog wouldn't be good for us. We have named the dog Trooper because he was found in the woods and survived. So far he has been great with our daughter. He doesnt care about her getting in his space even when he's chewing on his bone.He does love attention though and me being a stay at home mom am willing and happy to put the energy and time into him. If you have any advice or can give me more info on him I would greatly appreciate it.