That is pretty special. I would have teared up, too.
I have a funny story about my youngest step-daughter. When she was only 5 and her mom and I had only been dating for 6 weeks, she said she wanted to go to my work to help me wash my car there. I thought is was a little odd that she wanted to help me do that, but she came with me anyway. As we were washing my car, she stops and with the most serious expression, says, "Just so you know, I can never love you as much as I love mommy, because I've know her for 5 weeks, and I've only known you for 6 years." I had to contain myself from laughing because she got the weeks and years mixed up, but I kept a straight face because I knew what she meant. It was just so cute of her to say.
Now, 13 years later we laugh about that day. She barely remembers it but apologizes for saying it anyway. It didn't bother me. I know she was just looking out for her mom.