My kids were exposed many times where we lived when they were small and yet 5 weeks after we moved about 300 miles away, they both caught it and broke out within 24 hours of each other. Incuabtion time from exposure to break out is usually 21 days. My conclusion is there are some regional differences in germs. Interesting, huh?
I'd suggest you call your doctor before being in a school with chicken pox just to be on the safe side.
Wishing you well - Barbara