Yo, I'm a first year Computer Science college student, I've been thinking of pursuing a career as a Game Programmer. I was wondering since the only languages we are learning at the moment are Java and SQL, how useful is Java for developing games.
Should I self-teach other languages like C++ or Python aswell?

C++ would be useful, so would java. You could consider C# but do some research into it's usage as a game platform first. A lot of games are written with special game engines now so you could consider things like Unreal and Unity.
And graphics are, of course, very important so you might want to learn OpenGL or similar

SQL isn't going to loom large in a Game. Java hasn't been used much in the past for games, but modern Java and JavaFX is no worse than c#/.NET, and lot more portable.
However, the big question is "where does IOS fit (if anywhere) in your target gaming market?". IOS means Swift, which is a lot like c#, but is Apple-only.

When we talk about 2D games, Java might help you a lot of work , but if you consider to create 3D games that contains lots of resources Java will not help. If you seriously want to enter in game programmin consider learning C++ or C#. Most of game engines support C++ and C#. There are lots of books and tutorials on C++/C , C# and game development that will help you in self-teaching.