A little help? Parents of a 6-9 year old or 10-12 year old?

[KahluaCupcake]

I'm making jewelry for a friend's wedding party, and there are four girls, I believe aged 6,7, 10 and 12 or thereabouts. She hasn't gotten them, but I need wrist measurements. I have no idea how big or small a wrist is on a girl, especially 6-7. I nannied a girl who was 7, but honestly, she was a twig so I dont know how that tiny wrist compares to average girls.
If someone could measure their kids' wrist or even if you only have a flat ruler, measure a bracelet they already have, i would greatly appreciate it.
Thank you so, so very much in advance for any help!!