is this considered rude?

[CEDmom]

If you can't or don't want to go then don't but to be rude about it is uncalled for. It's a birthday party for goodness sakes and chances are if invitations were mailed a year in advance someone probably wouldn't be able to make it or would have to cancel. I think we often forget that while we live in the same country we don't all go by the same etiquette rules. What's rude to a northern is not necessarily rude to someone from the south etc. This family was trying to do something nice and somebody took the gesture the wrong way. Also, because it was short notice I don't think it would be rude to tell the birthday girl that you didn't have a chance to get a present yet and will bring it by in a few days.

 

[CookieGVB]

I'd be annoyed at a 3-day invitation because of the gift-shopping factor.

The fact that it's on a holiday weekend may mean that fewer people will go anyway. 3 day notice will mean fewer still. If I had to chaperone a bunch of 13 year olds at an amusement park, that might just be the way to do it.