My daughter is going into 7th grade and we allowed her to shave her legs this summer.
I taught her how to do it with a razor and shaving cream. I made sure it was a nice razor because I think it's easier to cut yourself with a cheap one. She does a good job, she misses hair occasionally but I figure she's just learning. She hasn't cut herself yet, but I did warn her about mosquito bites and she did take a small amount of skin off a mosquito bite.
I taught her to do it while sitting on the edge of the bathtub because I felt it was safer that way than doing it how I do it which is standing in the shower with my leg on wall LOL!
My mom insisted that electric razors were safer, but my daughter seems fine with a regular razor and shaving cream and I think they give a closer shave. Not to mention the big cost of buying an electric razor vs the small cost of a regular one!
They grow up so fast, don't they?