I would absolutely NOT cut my trip short!!!! You have your trip planned and paid for, it's a done deal. 3 months away is extremely short notice for a wedding, and i'm sure everyone knows that you'll be away on that date. Send a lovely gift!!!!! And if I was planning a wedding with such short notice I would make sure everyone that I was close with was able to attend on that date. If it were a huge issue that you be there, i'm sure they could have put it to the weekend before or after!!!!