The 5th Birthday in Two Weeks

I have been trying to wrap my head around the idea that I have worked with this woman for several years and not known when her birthday is celebrated.  I was speaking to one of the crew members at my part time job about the birthday gifts I got for someone at my full time.  As we chatted she mentioned having to work on her birthday and waiting til New Year's to celebrate.  I realized her birthday occurred this weekend.  Luckily I was able to get her a gift on short notice she could enjoy.  I am still dumbfounded.  Five birthdays within two weeks on each other.