My fiancé’s sister isn’t going to make the effort to come to our wedding.

My fiancé and I are having a destination wedding. While normally this could be viewed as selfish to begin with, our families are on opposite ends of the country, to the point where traveling would be involved period, so we figured we would have it overseas. The country where we’re having it is extremely affordable, like, cheaper than traveling domestically. The trip will cost about $2500-$3000 a person for everything for one week. My dad is taking care of everyone’s transportation at the location/tour buses/sightseeing. It’s quite a long trip, takes around full day of travel to get there, so anyone coming has the option to stay about a week and have free, quality touring and activities. My fiancé’s parents will be coming, but from what they’ve told me, his sister doesn’t really want to go. I was going to ask to be a bridesmaid. I don’t talk to her at all, except for the occasional “happy birthday” and “merry Christmas”, we live on opposite ends of the country, but if she were there, she would be the only young female left out and I thought it would also be a good chance to bond. I’m really trying not to feel insulted considering she wouldn’t have to pay a dime (her parents have the $$ and would cover her), she also HAS the money herself, no job or obligations, and has no problem traveling 9 hours to see her in-laws. Am I in the wrong for thinking it is extremely selfish of her to snub her brothers wedding like this?