Friend Wants To Be Bridesmaid

I am having a really big problem. Last month I was a friends maid of honour and she told me that only reason I was her maid of honour is because I would write the best speech. I had no prob with that. But my finace and I are getting married now, and last week she told me she would be extremely mad if she wasnt in my wedding. I dont know what to do becuase I already have three bridesmaids and she is not one of them. I dont want to hurt her feelings but I dont want to ruin my day to please everyone else???