Everytime you look at the quilt, the errors will jump up and smack you in the face. You have to fix them or hate the quilt forever. I'd say, take off the two dark pink side borders. Add a fairly narrow lighter pink border all the way around and then the dark pink. If you cut it wrong, and that is why it is narrow at the top, cut another one. If you don't have the fabric to cut another, cut the other borders down to that narrow width and sew them back on. You've obviously put lots of time and skill into it so far, hang in there and you'll be proud you did.