The event is expected to welcome about 100,000 people this year, with headliners such as Charli XCX.
Tilly is most excited for Sunday, when Florence and the Machine and Chase & Status will take to the stage.
“Just get out of your comfort zone, it’s not as scary as you think,” she said when asked about her solo visit.
“It’s scary getting there by yourself at first but, once you’re there, it’s so easy to make friends and you’re going to have a great time.”
She said a few people were “surprised” at her decision but she had enjoyed last year.
“My friends couldn’t get tickets last year, and I just had such a great time, being able to just go and watch whoever I wanted and not have to think about who everyone else wanted to go and watch, so I thought I’d do it again.”