If you are having problems learning OpenGL, I know how you feel. OpenGL is confusing and is very easy to give up learning it. But hang in there. Let me share with you my first struggles with OpenGL.
So, you want to develop a game engine? That is great! The good news is that you will learn so much about computer graphics. Your programming skills will improve x10. You will no longer be the same. Now the bad news:
It has been a while since I gave an update on my engine. The truth is that I have been working hard on it. I was finally able to get the GJK algorithm and the EPA algorithm to work properly in the game engine.
Many many many times it seems as if I'm not progressing in the game engine. I tend to obsess about the architecture of the engine. I move things around, put them back, completely modify the engine until I have something that I think is optimal.