What does "little" mean here?
Answer from a Native speaker
"Little" in this case is used with "miss" to give the nickname "little Miss New Boobs" to Ross' new girlfriend. "Little miss (something)" is a nickname given to a woman you don't like or that you think is pretentious and snobby. This title has a very sarcastic nuance and the word "little" belittles the title of the person and makes them appear small and insignificant. Ex: Here comes little Miss Perfect. Ex: Oh look, little Miss Good Grades is bragging about her achievements again.