Is a girl obliged to obey her mother by not going to the mosque for fear of harm, especially since the girl lives in a European country and sometimes prays in the mosque?

A woman is not obligated to go to the mosque for prayer, and it is better for her to pray in her home. Obedience to one's mother is obligatory, provided that such obedience does not involve disobedience [to Allah]. Therefore, the girl must obey her mother in not going to the mosque, especially if her going would result in harm or damage.