My daughter was 12 when I let her start shaving. You know when they need deoderant. (you can't miss the smell) My guideline is this: When your daughter gets the underarm hair, then it's time to start shaving. Take her to the store and look over the available products. Both of you decide what would be best for her. Tell her what is good and what isn't.
Open communication will be a key factor in how bad puberty is for the both of you. My adolescent years were not exactly happy ones since my mother didn't even want to face them. To her, if you didn't talk about it, you didn't have to deal with it.
I've learned from this experience and try to talk to my daughter no matter the situation. I try to make sure she doesn't have any questions that go unanswered. This includes everything from grooming and hygiene to sex and boys. (Thanks the Gods she doesn't like boys yet!!) I let her know that there is plenty of time for her to grow and become the woman she's destined to be. I'm there to support her and help her through the growing process.
The two MOST IMPORTANT THINGS TO REMEMBER:
1) Keep your sense of humor.
(if you can laugh about it, it won't seem as bad)
2) Remind her everyday that you love her fiercely.
(this is why sometimes you have to say "NO!")
Good luck and keep laughing!!
K.