Vowing if Allah grants her a son to marry him when he is 15

Q: I used to give birth to girls only. I made a vow that if Allah grants me a boy, I will help him get married at the age of fifteen. However, I am not sure whether I said fifteen or seventeen. There is only a month and a half left until my son becomes fifteen years old. (Part No. 23; Page No. 373) I do not own anything, given that I am a housewife; I am neither educated nor employed; and my husband earns a very little salary. We are indebted, and my husband's salary is only 2,000 Riyals. My family consists of ten people, and only Allah knows our status. However, even if we can afford it, my husband refuses to let our son marry at that age. Please advise.

A: If you cannot fulfill your vow due to your financial insolvency when your son reaches the age of seventeen, as this is the maximum possible age, you have to pay Kaffarah (expiation) of an oath, and there is no blame on you. The Kaffarah is feeding ten needy people, a kilogram and a half of wheat or rice or the like each, clothing them, or emancipating a believing slave. If you cannot do either, you have to observe Sawm (fasting) for three days to expiate for the vow.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.