Praise be to Allah.
This is one of the plots of the Shaytaan by means of which he discourages people from calling others to Allah and from enjoining what is good and forbidding what is evil. For example, he makes them think that this is a kind of showing off or that people will think he is showing off. You, my sister in Islam, should not pay any attention to it, rather you should advise your sisters and your brothers if you see them falling short in any duty or committing any sin such as backbiting, slandering, or not covering in front of men. Do not be afraid of showing off, rather focus your intention on Allah and be sincere towards Him, and be of good cheer. Ignore the plots and whispers of the Shaytaan. Allah knows what intention is in your heart and how sincere you are towards Him and towards His slaves. Allah knows that showing off is shirk and it is not permissible, but it is also not permissible for a believer, man or woman, to stop doing what Allah has enjoined, namely calling people to Him and enjoining what is good and forbidding what is evil, for fear of showing off. So you have to beware of that and do what is obligatory in the midst of men and women. Men and women are equal in this regard. Allah has explained this in His Book where He says (interpretation of the meaning):
“The believers, men and women, are Awliyaa’ (helpers, supporters, friends, protectors) of one another; they enjoin (on the people) Al-Ma‘roof (i.e. Islamic Monotheism and all that Islam orders one to do), and forbid (people) from Al-Munkar (i.e. polytheism and disbelief of all kinds, and all that Islam has forbidden); they perform As-Salah (Iqaamat-as-Salah), and give the Zakah, and obey Allah and His Messenger. Allah will have His Mercy on them. Surely, Allah is All-Mighty, All-Wise” [al-Tawbah 9:71]