It just means the cat loves you and trusts you. Cats instinctively "knead" or massage when they are comfortable and around people/animals they trust. They knead on their mothers stomach when they nurse to stimulate the flow of milk, and it's a habit they might keep into adulthood.
I'd also hope you're taking that 11 week old cat to the vet, that's awfully young to be separated from the mother cat. Cats need to be weaned before they're taken in - but if you just picked her up with no evidence of the momma cat being around, take her to the vet to make sure she can eat solids with no modification. Kudos to you for adopting the kitten!
Decent article on weaning -
http://www.petplace.com/cats/weaning-kittens/page1.aspx
Basically, it's normal. My cat will knead and attempt to suck on one of my soft fleece blankets - it's hilarious (she's two years old)!