Hello, and welcome to PT.
You must be a new cat owner? Well, you've come to the right spot for all your questions and needs. There's a lot of great people on PT.
I hate to be the one to break it to you, honey, but kneading is what cats do to get ready for bed. They knead their space to soften it and relax themselves. It is a natural thing for cats to do, and there really isn't anything that can be done to stop the habit. It is also a sign of affection, so the cat is comfortable with you and appreciates you giving her a new home. Sorry....