Backing out of a destination wedding?

This has been weighing on me. A girl who I am not very close to asked me to be one of her bridesmaids in a wedding in India this winter. At the time, she said almost everything would be paid for for the bridal party (part of tradition), but that’s no longer the case. The flights alone are about 2k, then we need different outfits for about 5-7 events. I dislike her friends and family, and I am just dreading this. I just am too scared to tell her I don’t want to go. Do you think I can? The wedding is 5 months away.
1) since I committed do I 100% need to go?
2) should I just tell her I am very sorry but I have anxiety about the cost and distance and can’t come?
3) any ither ideas?