I was riding my bike around this evening and I went up a curb sideways and the tire, rather than going up on the curb, continued on into some direction but I didn't see where because it happened so fast. Anyway, the bike fell over along with me and my knee hit the ground and net my chin.

I was planning on going MTBing at South Mountain in AZ this weekend but I feel that I would only be falling the majority of the time. I have gone MTBing when I was maybe 6 or 7 and I ended up flipping my bike over and my entire arm scabbed over, and also last year with another bike. The second time wasn't nearly as rocky as the first so I came off unscathed and scratchless. But I'm having second thoughts now. I barely went up 2 inches and nearly broke an arm. I'm not exactly proud to say this but... I wasn't wearing a helmet. I'll definitely wear one if I go MTBing and also knee and elbow pads but I still worry about falling alot.

Does anyone have any tips for a somewhat first time mountain biker? Should I take extra precautions and not go so fast? Or just be careful if I do go fast?

Any advice is welcome,

Josh