Okay So I have been coding 2d games in C++/Allegro for nearly a year now. I've made handful of games/demos:

Zelda

Sonic:

Super Mario

A Soundboard

1942 clone:

Pong/Breakout:

For my next project im thinking of trying out 3d using opengl with allegro. But my main concern is that I might forget all this 2d stuff I have learned and biting more than I can chew. But I want to try something new especially since I have more time in the summer. I don't know what to do: continue making 2d games or try out 3d? What do you guys think?

If you ever want to make 3D games, you have to start sometime.

You won't 'forget' all the 2D stuff you've learned, as you'll end up using a lot of the techniques and things anyway, and a quick review will get you back in the saddle if you decide to go back.

If you're perfectly happy making 2D games and feel that's where you want to be, then by all means keep getting better at it.

There's tons more to the world of 3D and it looks daunting at first, but all you're doing is adding a new dimension!

Go for it dude.