Why can't I learn German?

Seriously. I've tried. All my freinds from high school and college who have taken German cles have all ped. Me? I flunked it in high school and had to repeat it several times! College came and I got no further! I had to drop once or twice and flunked some! What's wrong with me? It's not like I don't want to learn. I'm eager. Why can't I learn German?