Makeup, every parent has to cross this hurdle when they have a daughter. Some parents are able slip past it if they have a bit of a tomboy, but more likely than not it is going to come up. Your daughters go from cute little babies that try to eat your lipstick or smear it on walls to near hormonal teens that want nothing more than to wear it. Maybe they want to wear it so they can be pretty like mommy, but more likely they want to wear it because all their friends do. Peer pressure is still a sad reality in schools. You may not want to hear that she wants to wear makeup because "all her friends are" but that is almost always why they are driven to ask.
However, when do you know your daughter is old enough? This topic should start popping up seriously in junior high. You may want to hold it off until high school, but you would be lucky to do so. If your daughter is asking to use anything more than lip gloss in late elementary school, they are definitely too young. Though you would not think so from today's society where they market make up for girls as young as 8 years old. However, in the end, it is the parent's decision on when your little girl should start using makeup.
This issue is a valuable chance to try and teach your daughter how to ask and act more like the adult they should be to wear makeup and less like a child. If you tell them no and they whine, scream, and cry just solid your resolve as a parent. As an adult, when they whine, scream, and cry it will not get them anywhere and let them know that. Makeup is reserved for adults who can approach the subject like an adult and allow for compromise.
Though, every mother should remember how teenagers are. The more you tell them no, the more they want it. Maybe they start buying cosmetics in secret and putting them on at school. Maybe, since your daughter has little real sense in what is appropriate, they are using women like Kim Kardashian or Perez Hilton as examples of how much makeup to use. Women like that use so much makeup that they hide the person inside, that is definitely not what you want for your daughter.
When your child approaches you on the subject do not just say no and tell her she is not old enough yet. Try to handle it without finality. If you truly feel she is too young, set date that she may start wearing makeup. For example, in my family, my sisters and I were not allowed to wear makeup until the 8th grade. We knew that, every time we approached the subject that is what we were told. My mother never told us we cannot wear makeup, just that we have to wait. In fact, she encourages us to experiment with makeup once the date started to approach, just as long as we did not leave the house in it or with it.
Makeup also proves as a great opportunity for some nice mother-daughter bonding. When you decide to let your daughter wear makeup, also help her shop for it. Some women have a natural sense for what looks good on them, but most young girls need a bit of guidance. It may take awhile to find something that really works for both you and them. Your daughter might think that red lipstick, blue eye shadow, and bright red blush might look awesome, however you might (and should) feel strongly against it. Aim for tones close to their skin tones, start with more neutral tones at first. Perhaps make room for compromise. Let her have blue eye shadow--I mean, who didn't go through a blue eye shadow phase at one point?--if she agrees to pick a more natural lipstick and blush.