Little Girl is how captions refer to a girl who says "I play a little every day" at the start of I Am Johann Sebastian Bach.
She plays "Twinkle Twinkle Little Star" on the recorder and Xavier is envious. Later in the episode she plays "Mary had a Little Lamb".
At the end of I Am Eleanor Roosevelt it also appears to be her, but in a different outfit. A sleeveless light-purple dress. She still has the same ponytail and the same turquoise stud earrings. Here she is clutching a green triceratops toy.
Xavier recommends she go see Murray.