Donna was born on a holiday --- which one was it?

isnt it Christmas...im not for sure, but for some reason that popped into my head as soon as i read the question!

Yes Donna was born on Christmas--there were several episodes where the group made a big deal about her birthday being on Christmas.

The more interesting birthday to figure out is Kelly's--in season 3 she has her 18th birthday towards the end of the school year; however, in their 3rd year of college, her birthday was celebrated at a concert in the early fall?