I agree with knitnj; size 11 are perfect for a beginner. Also, I'd use plain old straight needles and not circulars, because circulars can be somewhat confusing and scary to a new knitter. I would also suggest a really fun and cheap yarn from your local yarn shop. I have a couple peaches and cream, but for the life of me, I just don't like the feel of it.
All in all, I hope you two have fun =)