How do I step out of Maid of Honor acceptance?

About a year ago, my friend and I got back in touch after 17 years of absence. She asked me to be her Maid of Honor last December after her boyfriend proposed and I dumbly said yes. I guess because we were best friends then and friends again and thought things would be like before. I have found that I really don't know her anymore and have learned some unappetizing things about her (her comments towards some people and her actions). She is a person that I was close with, but we are strangers now and I only said yes I was flattered more than anything and maybe jumped in instead of thinking about it because I maybe thought things would be the same as before. I want to tell her that I don't want be her Maid of Honor anymore before it gets too late. I live 3 hours away from her and I don't know her like I used to or her family or friends. I feel bad for her because I don't think she has alot of friends and her family is a little unfettered by her upcoming nuptials and not helping her at all. I just don't want to be her Maid of Honor and she isn't the person I thought she was and maybe there was a reason why we broke off in our own directions 17 years ago. I tried telling her to be prepared if I can't be her MOH because at the time I said "yes", I had no job, and she knows I am working now. I might be a bad person, but I just don't really like her anymore hearing her racist comments and her "woe is me about everything in my life except my DESERVING to get married" about everything in her life attitude. Any suggestions??