Answered by Shaykh Yusuf Weltch
Question Summary
Am I responsible to fulfill a vow that I made prior to reaching puberty?
Question Answer
In the Name of Allah, the Most Merciful and Compassionate
No. You are not responsible to fulfill any oaths made prior to reaching puberty. The Messenger of Allah (may Allah bless him and give him peace) said, “The pen is lifted (i.e., they are not taken to account) for three people: for the one sleeping till they awake; for the child, till they reach puberty; and for the insane, till they regain sanity.” [Abu Dawud]
Hope this helps
Allah knows best
[Shaykh] Yusuf Weltch
Checked and Approved by Shaykh Faraz Rabbani