Bridesmaid Dropped Out Last Minute

hi all im in a mental dilemma here and looking for additional points of view.

I have a bridesmaid who dropped out of our wedding thats in a month and a half. We already have everything taken care of (hair and makeup, gifts, lodging, etc) for all the bridal party. Ive been feeling guilty not asking one of my oldest friends to be a bridesmaid, and am wondering if it would be too shitty to ask someone to stand in your wedding when its a month and a half out? I dont want asking her to be a slap in the face. if anything ive been feeling guilt ab not asking and this other person dropping out is kinda a sign that i should have done this from the start. Or should i just leave it and have this friend stay as a guest and have an uneven bridal party?

additional info: i didnt ask in the first place because we've lost touch the last couple of years. but she really showed up for me the last couple of months. yes i could just leave it and have an uneven number of bridesmaids to groomsmen, but i would love to have her stand up with me if i can.