I’m in my early 20’s and I started to shave in 4th grade after being tormented and picked on by the other girls in my ballet class because my armpit hair looked like a grown man’s.  Besides being a foot taller than everyone I had to have my feelings hurt over this.  It still bothers me to this day, and if your daughter is self-concious about her hair then I’m sure she will learn fast enough how to handle a razor.  I have LOCAH, and had a problem with sweaty armpits, and b.o., so shaving will help with that.  An electric razor does not give a close shave, so teach her how to use the razor and just relax.