You must never feel badly about making mistakes. . . as long as you take the trouble to learn from them. For you often learn more by being wrong for the right reasons than you do by being right for the wrong reasons.
I know what you are known as. . . but to me, you will always be Tom Riddle. It is one of the irritating things about old teachers. I am afraid that they never quite forget their charges’ youthful beginnings.