updated 10/21/2010 AT 9:00 AM ET
•originally published 10/21/2010 AT 9:45 AM ET
By now, people should know it’s not a good idea to cross Taylor Swift.
On her new album, Speak Now, the singer, 20, not only calls out a “dark, twisted” game-playing ex-boyfriend (could it be John Mayer?) in “Dear John,” but the singer also gives a lyrical lashing to a harsh critic in “Mean.”
Swift tells PEOPLE the subject of her song is “a person who was repeatedly, constantly, perpetually ruining my day with the mean things that he was writing.”
She may be referring to music blogger Bob Lefsetz, who, to put it nicely, is not a fan of her singing and even wrote Tuesday that the song is probably about him.
Though she says she can handle people’s negative comments, they still sting. “I don’t have thick skin,” says Swift. “I feel everything.”
The singer, a former middle school outcast who says she’s “never felt popular,” has been dealing with nasty critics since childhood.
“I know what it s like to be standing on a little tiny stage at the local garden party, and this guy who s been bullying me all year walks by and starts staring and screaming up at the stage, and heckling.”
“Mean,” she says, “is about bullying at a different stage in my life. I m not at school and I still know what it feels like.”
Maintaining a balanced perspective helps her move forward. “I m very happy to say I have many more great and good days than I have bad days,” admits the singer. “That’s the goal and I m going to keep that as the goal, and we ll see what happens.”
Read more about Swift’s life now and her new album and in the new issue of PEOPLE, on newsstands Friday