Is what I mentioned considered a vow, knowing that I am not familiar with vows, but I promised Allah? And is it permissible for me to buy gifts for my children from the vow money designated for the poor and needy, and to encourage children to memorize the Qur’an?

The statement "I will give my salary" or "I promised God" is not a binding vow (nadhr (definition)). A vow requires a clear form of commitment, such as: "It is incumbent upon me for the sake of Allah to do such and such." Nothing is binding upon you if you do not recall what you said, because the default is that one's liability is clear (innocent), and certainty is not removed by doubt.