Does the questioner feel a sense of wrongdoing after denouncing an evil, especially when the perpetrator of the evil is older than them, and is this feeling natural after recovering from the delusion of extremism in religion?

The cure for obsessive thoughts (waswas) is to ignore them and turn away from them. Denouncing evil (munkar) is obligatory if you are certain it is evil, and it should be done in a suitable manner, even with those older than you. Rejoice when you perform this duty, for it is obedience to Allah. Strive to seek knowledge so you can avoid denouncing that which is not evil, or denouncing in an unsuitable manner.