Am I wasting my time?
Not wasting your time exactly, but judging by your thread last night where you said you were just starting with BlitzMax and not finding it easy, I'd say you're getting ahead of yourself. I highly recommend sticking with the official BlitzMax language and modules until you're much more confident with those.
I heard by word of mouth that OpenGL can speed up your game a lot.
You heard wrong if this was about BlitzMax. BlitzMax has an OpenGL driver and a DX7 driver built in. That's not to say that an experienced programmer couldn't do it better than Max2D does it, but Max2D already uses OpenGL if you want it to. You can use whichever you prefer ( unless you're on Mac or Linux in which case, there's no way to use anything *but* OpenGL. )
Look up SetGraphicsDriver in the documentation. Note that if you're on Windows, BMax will default to DirectX7, and you will need to set the graphics driver to OpenGL if that's what you want.