What is the ruling on the prayers and Ramadan fasts performed by the questioner without purification, due to her ignorance of the requirements of ghusl after masturbating, before she knew its ruling? And what must she do now?

If you repent sincerely of your sin, you become as if you had not sinned, for the Prophet, peace and blessings be upon him, said: "The one who repents from sin is like one who has no sin."

Do not deem your past prayers invalid unless you are absolutely certain that semen necessitating ghusl was discharged and you did not perform ghusl. The default is that your prayers are valid. If you are certain that certain prayers are invalid, there is a difference of opinion regarding the obligation to repeat them. The view that re-performing them is not obligatory is strong in terms of evidence, though the cautious approach is to re-perform them. We have explained how to re-perform them.

Your fasting is valid in all cases, even if you did this act during the daytime in Ramadan, for whoever commits an invalidating act out of ignorance does not invalidate their fast thereby, according to the preponderant opinion.