You're in the last gasps of adolescence -- no, it's not too late!
A book I'd highly recommend to everyone is "The Other End of the Leash" by Patricia McConnell. It's a look at how we (as primates) mishandle and misinterpret and generally bungle our interactions with dogs, because we're operating from one set of characteristics (the primate kind), and they another (the canid kind). For example, we greet by approaching straight on, looking in the eye, reaching out to the person. To a dog, that's a phenomenally rude way to greet.
Likewise, as primates we're hardwired to reach out with our hands and hug and manhandle and talk and talk and talk and talk. And all the talking and figeting is information overload for the dog, who usually will rely more on physical movements for information about what we want. Moving towards them is a direct order (in the dog's mind) to stay still -- and yet when calling a dog to us we generally will step toward it!
So we're saying one thing and doing another and wondering why the dog just doesn't get it.
It's not the least bit boring or academic but you'll learn a lot about both humans and dogs, and be able to catch yourself doing a lot of the mixed signalling. I know it's helping me.
Also can't recommend the Dog Whisperer on National Geographic channel enough. I wouldn't encourage people to do serious dog aggression work based on watching it, but for the common household rudenesses, and taking charge of an adolescent dog, you'll learn a lot, principally from how to walk the dog and establish authority and discipline.
The principle benefit of the show is demonstrating what he calls "calm, assertive energy." It's not about battles for domination, just stepping up, grabbing the leash, and taking charge.
As with the book, you'll spot your own weaknesses and mistakes in the examples of others.