I didn't get married until I was nearly 40 and my formal name goes better with my married surname than my nickname does. For awhile I figured I'd introduce myself by my formal first name but it's not quite "me" and I've never used it except on forms, etc. In college I didn't bother telling an instructor my nickname and she called on me by my formal name one day and I sat there looking around, waiting for that person to answer until I noticed everyone else in the class looking at me Of course, by then, I'd forgotten the question.