It went fine, and calmly. She got a homemade card from a friend (I sent out requests - seems like too soon, though, as the others forgot), a lovely card from classmates and teachers from school that seemed to surprise and touch her, generous cash gifts from her granny and magnanimous uncle and aunt, and cash from us that will let her buy the computer gamey stuff she'd been planning to save for. She was gracious about it all, even blew out candles, but did say she didn't want the cake around. I promised to make her one specially when she's eating cake again - that seemed to go down ok.
All is calm, she's playing a game she bought with her brother and I think we hit a balance of recognising the day without making a fuss.