"I wasn't planning to go until I turned 18 on the 24th (August)."
A representative for the actress and TV personality told People magazine the situation with Chelsea is "heartbreaking on every level".
Chelsea also dismissed claims made by Rosie's representatives when she was reported missing that the teen was living "with mental illness".
She told the Daily Mail she suffered from anxiety and depression when Rosie and her ex-wife Kelli Carpenter split and divorced in 2007.
"Putting out there that I am mentally ill was really hurtful," she said.
"People think I'm this crazy person and as I've said, I have depression and bad anxiety but it's been something that's gotten a lot better. But these were personal things and I didn't want anyone to know them about me... I wouldn't say I'm mentally ill, I would say lots of people struggle with what I have."
And talking about her relationship with Sheerer, Chelsea said: "I guess everyone is putting out there he's a bad guy from things that happened in the past but he's not. He supports me and I love him. He's not into anything bad now, he works hard."
The teenager told the publication she wants to complete high school online and then move to Wisconsin, where her birth mother lives, with her boyfriend.
- WENN