One of two things will happen when you tell people you're an author.
1. "You wrote a book? That's awesome! What's it called? I'll read it sometime." *Immediately forgets this conversation happened* "You wrote a book? That's awesome!"
2. They actually read your book and start idolizing you because HOLY CRAP, YOU'RE AN AUTHOR, and obviously every author is like Stephen King or JK Rowling so you must be a famous celebrity, and they start following you everywhere, and bragging about how they know you, and you're an author, and they can't go five minutes without asking if you've written another book yet, and go away, go away, GO AWAY!
If you couldn't tell, the first option is better.