If it were me, I'd get her a full sized machine and then buy some Hello Kitty decals. This way if and when she no longer wants Hello Kitty on her machine she could just take the decals off
You can get a Brother 6000i sewing machine with a lot more bells and whistles plus an extension table for less.
I know several people who have gotten this machine and are happy with it for beginning sewing/quilting. Add a package of decals, bam. You are good to go.
I think I heard that this machine is being discontinued, so if you want it, get it while the getting's good
I'm sure Brother has already released the machine to replace this model, but it's being marked down now. It used to be a bit more online. Walmart.com is now sold out of it but there are still some left on Amazon - free shipping and no tax (depending on where you live)
http://www.amazon.com/Brother-Featur.../dp/B000JQM1DE