Super, super impressive stuff. I've done a tiny bit of OpenGL (As in, rendered some triangles on a screen, made a simple shader). I'd love to give a 3D framework a crack sometime.
And yeah, I imagine skeletal animation is extremely far from trivial to implement, so that does make things tricky. Keep up the good stuff, it's really nice to see people are still making games "The hard way", as I think it's a really, really good way to understand what actually goes on under the hood, and that knowledge is useful even if you do end up using an existing engine. Not to mention, great for improving your programming skills.