I think it really depends on the individual child....
Some children are much more mature than others at certain ages.
At 12 I knew what oral sex was, and by 13 I was doing it. Not because I was a "hussy" or because of sex ed but because its natural progression into adulthood and different teens go at different paces.
At the end of the day she needs to know these things. By the time I was having sex ed I was very educated already on everything I knew. I have a very close relationship with my mother and she told me everything I needed to know.
Having the information early meant that I knew what I was doing and what I was getting myself in for. I have never had an STI or unwanted pregnancy, nor have I had any negative sexual experiences. Had I not been given the information I probably still would have lost my virginity at 14 but probably under completely different circumstances.
I have spoken to young teens who are having sex but believe such myths as "if you have a bath after sex you wont get pregnant"
Or "only dirty people will give you an sti"
You can always request that your daughter is taken out of these classes but what good would it do? shes probably seen it on tv anyway!