- Jul 26, 2018
Dawn was already 14 when she arrived in s5 in late August/early September of 2000 (they talk about that week being the end of summer and it was right when classes were about to start again). In The Real Me Dawn said she is 14. She was still 14 by Buffy's birthday in January 2001. In All the Way Buffy says Dawn is 15 and that was in October 2001 since it was Halloween. In OMWF she sang "I'm 15 so this Queen thing's illegal" and that was in November 2001. Still 15 in Gone which is in December 2001.That isn't canonical. Not within the seven seasons of the show - and I certainly don't count the comics, if that's where you're getting that fact from. Besides what they later decide for comics has no bearing on what has already been written. Within the canon of the show we know she got called in 1996 because we see it happen, but the exact date is never mentioned.
S1 Buffy is 16 when she turns up. Dawn is 15 in 'Gone' - because Doris says so. She does not have a canonical birthday so we do not know exactly when her birthday falls. She starts sophomore year at the start on s7. I think sophomore year is the equivalent of y11 in England - she would be 15 in that September and turning 16 sometime in that school year. Presumably she was a fall baby - if she was 14 in blood ties and 15 in Gone, but not 16 before the summer ( which would make her a school year older - but she is definitely a sophomore in 'lessons' - because she said she was a freshman in the Halloween episode. ) Buffy is mid sophomore year at the beginning of season 1. Any Dawn we see prior to about 'sleeper' is younger than S1 Buffy. And has already lost her mother 18 months previously - whilst 15/16 year old Buffy still had hers.
In Shadow she said she had her 10th birthday at the carousel soon after they arrived in Sunnydale. It's more probable she mistakenly meant her 11th birthday since the timing of their arrival in Sunnydale had to be in January since the ritual in The Harvest was on the first moon after the solstice. The summer solstice is in June and the winter solstice is in December. And in Welcome to the Hellmouth Joyce said Buffy was 16 and in Witch Buffy said she had been slaying over a year. So subtract an entire year from an episode that took place not long after January 1997, that puts you in January 1996. Also, it wasn't the beginning of the school year for anyone else in s1 highlighting Buffy was most likely a beginning of the spring semester transfer. Also why Buffy needed to play catch up.
Since Buffy's birthday is in January and she became a Slayer when she was 5 and the flashback to her finding out she was a Slayer took place in 1996 she had to have become a Slayer at the beginning of that year.
So going from canon from the tv series, Dawn's birthday is in February or March.