Is it normal for a cat to lick her stitches?
Yes. She feels that it is something unnatural on her body, and wants to remove it. It may also be because it is itching. Try to discourage her from licking them, as she could accidentally pull them out. If nothing works, you may have to get her a cone.
Ask your vet to but a cone on your dog. Also putting her in a piece of clothing would prevent her from getting at her stitches. If she is just licking them it really is not a problem. It's perfectly normal for a dog to lick it's wounds. As long as she is not trying to pull the stitches out I would not be concerned.