Kiddushin 44 - Marriage and Divorce of a Minor
We have learned previously that a man may betroth his daughter when she is a naarah (between 12 and 12.5 years of age).
A related teaching: a betrothed naarah whose husband wishes to divorce her, either she or her father can receive her bill of divorce (Get), and any girl who is unable to take care of her Get cannot become divorced.
However, regarding kiddushin, her father accepts the kiddushin, and she can not.
Can a naarah appoint an agent to accept her Get? - No, because she has less power than her father, who alone can appoint such an agent.