Kneading and first litter size?

Kneading is a sign of thinking of you like a mommy. It is done to calm the cat. They will sometimes do it purely out of affection but purring and rubbing on you is a more common sign of affection. Since your cat is pregnant, her hormones are changing while she gets ready to give birth. A cat litter can be as little as 1 kitten up to as many as 10 kittens. Five is average. I had a cat in a similar situation last summer and she had 4 kittens. Technically you can spay the cat while she is pregnant but it aborts all of the kittens. A lot of vets are willing to do it due to the overpopulation of cats and the fact that a lot of kittens end up at the pound and put to sleep. A cat under a year old is at more risk health wise giving birth than an older cat. Since you seem to have chosen to let her have the kittens, make sure you feed her well now and after she gives birth so she has the best chance of having healthy kittens