Is zakat obligatory on the gold of a deceased woman that has been kept for seven years, given the ignorance of the obligation of zakat in previous years?

It is not permissible for a man to use a gold watch. If it was acquired for the purpose of saving, or for impermissible or disliked use, then you must pay zakat (definition) on it. As for jewelry that you acquired through inheritance, a gift, or purchase, you are not obligated to give it as charity; rather, it is permissible, and you must pay zakat on it for all past years if it reaches the nisab (definition) (minimum threshold) by itself, or when combined with cash or commercial goods. If the jewelry does not belong to you, then you are not obligated to pay zakat on it, and it is not permissible to give it as charity; rather, it must be given to your aunt's heirs.