What is the ruling regarding 'Umrah performed by a menstruating woman out of ignorance of the Shar'i ruling, and what are the consequences for her after eleven years have passed since this 'Umrah?

You have undoubtedly erred in what you did. Whoever performs Tawaf while menstruating must follow what is explained in Fatwa: 111341. By reviewing it, you will find that the easiest option for you is to act according to the opinion of the Hanafis, and to slaughter an animal as an expiation for performing Tawaf while you were menstruating. In this situation, your marriage is considered valid.