She is the first person to go back to mother! (4)
I believe the answer is:
emma
'she' is the definition.
(I've seen this before)
'the first person to go back to mother' is the wordplay.
'the first person' becomes 'me' (first-person pronoun).
'to go back' says the letters should be written in reverse.
'to mother' becomes 'ma' (ma can mean mother).
'me' in reverse letter order is 'em'.
'em'+'ma'='EMMA'
'is' is the link.
(Other definitions for emma that I've seen before include "Lady - Hamilton, mistress of Nelson" , "novelist's work" , "Ack -, a term for a.m." , "book" , "Austen character" .)