I think your putting the Cart in front of the Horse.
Your trying to explain to someone who already shows signs of little/abdlism, what little/abdlism is.
Really what you should be doing is talking with her to find out exactly how inline her interests are, with your own. sharing the things within abdl that make you happy, and discussing if she believes some of those would make her happy.
AFTER you have talked about the details, then you can tell her: "oh btw, there is a name for people with interest in this sort of stuff"
Otherwise, your identity is defined by broader society's idea of abdl, or the internet's, rather then HER own, or even YOUR own.