Why do you want a dog your dog's age? That can be a bad mix. Really. It sounds like your dog needs more time and training, and exercise, and then proper management when you cannot supervise. Adding another young dog into that mix can actually cause more problems than it helps.
Then you have two dogs, possibly equal in status within your pack, and both requiring plenty of exercise and training.
You should NEVER get a dog for your dog. Your dog does not need to bathe it, train it, groom it, feed it, vet it, exercise it, etc. The decision to get a second dog should always be because YOU want another dog to work with, etc.
Be that as it may be. If you want a second dog, usually it is best to get the first dog pretty well-polished before bringing in a second dog. And then, go for a dog with a bit of a gap in age. Male-Male can be ok, especially if we are talking altered rescues. Male-female is usually ok -- always there are exceptions. Female-Female can be tricky regardless.
But getting a second dog because the first one is having some problems, is usually not a good idea. It's kind of like having a baby because your marriage is on the rocks.
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