Nice job Jon!! Yes she may have overreacted, but what really matters is her feelings and to HER it was a big deal. The only thing you might have done differently is this:
"I told her it was ridiculous"
Don't do that, you're negating her feelings when you do that. Do give her reassurances, but remember to validate! "You sound angry, I'm sorry that you feel that way. It was really a misunderstanding, watch and I'll de-friend her now." Something like that. But the flowers were a nice recovery
