2,814. Investigating a Minor the Entire Year
Hilchos Nedarim 11:2
Pursuant to the previous halacha, if a minor makes a vow or consecrates property at the start of the year, they are interviewed. If it’s found that they understand to Whom the vow was made, the vow is upheld. If they vow again, even at the end of this year, they must be interviewed again. We don’t say that since they understood at the beginning of the year, they need no longer be interviewed. Rather, we interview them that entire year.
Hilchos Nedarim 11:3
Before the aforementioned ages, even if they say that they understand to Whom they vowed or sanctified property, their vows and consecrations are ineffective. Once this time has passed and a boy is 13 years and a day old and a girl is 12 years and a day old, even if they say that they don’t understand to Whom they vowed or sanctified property, their words are binding. This is true even if they haven’t yet developed the physical signs of maturity. This is the age at which vows are effective according to all sources.