Well, if you had it as a kid, I think it's highly unlikely you'll have it again as an adult. I've never heard of anyone getting the chicken pox in adulthood after having it as a kid. I myself have had chicken pox twice, but they were both during childhood.
I think you and your child are perfectly fine - if you have not broken out into the classic itchy sores, you have nothing to lose sleep over. You say you saw your friend on new year's eve, and the date of your post is january 9th. You would have definitely been itching yourself silly by now.
But, if you are still very worried, it never hurts to give your doctor a call and just ask them. Might be more reassuring to hear your doctor tell you you're fine than a random internet junkie, but who knows. :)