Hi D.,
I would talk to your peditrician about it. But, yes, Dairy and meats are the biggest nasties as far as hormones. It's because they get stored in hte fat.
Make sure she is getting a balanced diet, and some good vitamins.
If she isn't showing other signs: breast development, hair growth, etc... then I think you still have some time before things really kick in.
Also, just to comment on the growth thing that was mentioned by another woman. I was 13 when I started my period and was 5'4" tall. (I remember because I was so proud I was the same height as my mom!) I am now 5'10". I continued to grow through highschool. So, while it may be true for some kids that they have reached 85% of their height by puberty ... I don't think it is true for all. Just like anything else.... not EVERYONE fits the 'this is supposed to happen' mould. Physiology and medicine are not a 'one size fits all' type of thing.
Talk with your pediatrician and ask the hard questions. I'm sure it will make you feel better.