You can check the Classifieds -> Hobbyist Projects here at GameDev. You might find a team that wants a junior programmer.
You're probably better off on your own though. Lots of times there's the "idea guy" who says he needs programmers and artists. He has the next Big Idea TM that's going to make tons of money after you and the artist do all the work for free of course. Point is, there's not much to learn from in an environment like that.
If you decide to go your own route, start with small projects and work your way up. Here's a great article telling you which games you should build first and why:
Since you're learning C++, you might try the Unreal Engine. Or if you want to start learning C#, you could stick with Unity.