The title references the song "Mammas Don't Let Your Babies Grow Up to Be Cowboys" by Willie Nelson.
As Hannah Montana performs for the Queen's granddaughter, her granddaughter does not portray any granddaughter of Queen Elizabeth II. Ultimately, the closest in age to the character would be either Princess Eugenie or Lady Louise, but at 16 and 2 years old, respectively, at the episode's air date, they don't reasonably fit the age of the character.