Is the prayer invalid if a woman prays standing, making gestures for prostration, when she is unable to sit or prostrate, and she should have sat on a chair? And what should she do about the many prayers she performed in this state and does not remember them?

He who gestures for prostration from a standing position while capable of sitting and gesturing for it from a sitting position, has erred. This is because one who is unable to prostrate gestures for it from a sitting position to be closer to the ground, and gestures for bowing from a standing position. The majority of scholars hold that one who misses a pillar out of ignorance must make it up, while Ibn Taymiyyah disagreed, stating that it is not obligatory to make it up. If this recurs such that it becomes difficult to rectify, there is no harm in following Ibn Taymiyyah's view.