I don't really see any actual problem, long as she's aware of the effort that will have to go into them...unfortunately dreads are not an instant perfect do...they do require maintenance. The only other thing, is other kids. Kids can be mean. is she likely to cop any ridicule from others her own age? Other than that, I don't think there's much of an issue.

re: little white kid dreads...you'd go about the process and maintenance exactly the same as for caucasian adult hair.

Hey I just wanna say your kid is pretty cool for being open to dreads.
Hope it works out for her!
Peace.

Here is a gallery of other kids with dreads:

www.knottyboy.com/gallery/

My 5 year old has dreads! She'd been asking for an entire year, consistently, so I finally made them for her. It was much faster and easier than when I did my own. I wash her hair 3 times a week now, and when it dries I give each a brief palm roll. She doesn't have much patience for more, but it seems to be working very well. I should post pictures!!! They are SO darling on her... She had pretty baby fine hair to begin with, and it still worked fine. About a week ago, she said she had a dream that her dreads brushed out and she was scared that when she woke up, it would be true. She loves them!

I think its awesome , kids will make fun of you for one reason or another .. if your child likes em and cares for them correctly I say why not.... but be careful around other kids in school headlice in grade school is an issue and once infested good luck getting the lil buggers out of your locks