It wasn't just her birthday. It was a birthday episode!
In Buffy's prophetic dream, Drusilla said "happy birthday Buffy." The Scoobies and Angel plan a surprise birthday party for Buffy. When Xander shows Buffy the rocket launcher he says, "happy birthday Buffy, I hope you like the color." Joyce asks Buffy how she feels being 17 and reminds her that she'll pay for a mall trip during the weekend. Xander wanted to spank Buffy since it was her birthday (and he can be a pervert). Buffy crashes her birthday surprise party. Buffy tries to give the fact that it's her birthday as a reason for Angel not to leave the country that night. Angel gave Buffy a claddagh ring as a birthday present. A few days later Joyce gives Buffy a belated cupcake with a candle in it and asks her how she spent her birthday.
I remember some fans had a problem with so much emphasis being placed on Buffy turning 17 in Surprise since it made it hard to forget that Angel was deflowering a minor. I was okay with it since we are basically watching her enact The Hunger Games on a daily basis. If it's okay to watch demon after monster after bad guy try to murder her, with one even succeeding, and knowing that as The Slayer her chances of even surviving to her twenties would be slim, what's the big deal about the girl that has averted apocalypses and has a kill count in the hundreds or thousands, consenting to sex? If she's emotionally mature to have the fate of the world in her hands every week, then she is emotionally mature enough to sex Angel's soul out of him.
I wonder what Buffy did on her 23rd and 24th birthdays. It's not right that we didn't get a 22nd birthday episode in S7.
I am going to be so upset if Joss didn't plan a good lengthy issue for Buffy's 25th birthday. It's too legendary of a birthday to skip.
