It's a compliment, Lori! She loves the blanket you made her so much and has formed strong emotional ties to it--the new one has to be EXACTLY the same.
I've had to make several duplicates for my grandchildren too. One was cut to shreds by older siblings experimenting with scissors. The little one was heartbroken and mailed the blanket to Grammy to fix...she still doesn't know I had to make a new one. I did machine sew the tattered one as best I could and hid it away because it was so special to her.
Some blankets become a child's closest friend and comfort, and it sounds like you made one of those this time. It doesn't happen with every blanket I make, but when it does...I love it!