The Beach Boys band member will take to the stage at the festival, held on the Isle of Wight between September 8 and 11.
When asked whether he has considered retiring, the 68-year-old told the Evening Standard: "Oh God, yes. Another year, maybe."
"This could be the last time I play here. I'm going to miss it but I'm getting a little bit old for touring."
Wilson also revealed that he still suffers from stage fright, a hurdle he constantly had to overcome in the '60s and '70s.
"I'm always afraid just before I go on stage because I'm not sure how the concert's going to work," he said.
Previous acts confirmed to play this year's Bestival include Pendulum, Kelis, PJ Harvey and Santigold.