The Doctor shook his head emphatically. He didn't want Rose to think he'd just lied about being the last of his kind, but at the same time, there was so much she didn't know. And her questions weren't easy. They didn't have definite 'yes' or 'no' answers.
"It's complicated," he began with a sigh, although that much should have been obvious. He took a sip of tea, thinking over exactly where he could begin, and how to have any of it make sense. She had missed out on so much since she had been in her parallel world.
"Let me try to start... close to the beginning. I said she was at school with me. She was a friend, a best friend, along with Kos- The Master, remember I asked you about the Master?" he reminded her, pointedly.
"The three of us were close. We used to skip class and spent most of our time talking about how one day we'd get off of Gallifrey and see what else was out there," he admitted, with a cheeky smile, since Rose knew that the dream had certainly become a reality for him. "She was very smart and didn't really need school. I, on the other, could have done with going to a few more classes, and in the end I only scraped a pass because she kept letting me copy her homework, so you can see- on one hand, yes. I should be happy," he told her, with a nostalgic smile.