Mishnah for Yevamot 13:6

A minor who has not yet produced two [pubic] hairs: Rabbi Judah says: his terumah is terumah. Rabbi Yose says: if he has not arrived at the age when his vows are valid, his terumah is not terumah, but if he has arrived at an age where his vows are valid, his terumah is terumah.