AITA for not moving our destination wedding to the U.S?

My fiancé and I are getting married next March 2025 in Greece. We have had this wedding planned since October of last year. My fiancés brother’s girlfriend just found out a couple of weeks ago she is pregnant and is due around that time. Mother in law now wants us to have the wedding in the U.S because he can’t go since it’s close to her due date and she doesn’t want to go since it’s close to her due date. We’ve had the venue booked for almost a year now and have put a lot of money into the wedding (a good portion is non refundable). We have 9 people that have already booked their flights for the wedding. I told her that we cant cancel anything because not only will we lose out on a lot of money, but so will some of our guests who already booked flights. She is very upset and now not speaking to me and my fiance and calling us selfish. Obviously if we had known this way prior we wouldn’t have booked it around then, but we have had it booked since October of last year and the venue we got is our dream venue and very hard to get. We even told her if they can’t make it we would be willing to have a small reception in the U.S when we are back so we can celebrate with them. Now we also have his brother and his girlfriend messaging us calling us selfish for not moving the wedding, and because Greece is a place he’s always wanted to go and now can’t go and that we are taking away from their moment and we should move the month (which again we explained we would lose out on a lot of money and so would our guests that already got their tickets. Am I the asshole for not moving it to the US or cancelling the wedding?