LEWIS Hamilton said he was determined to leave Mercedes on a high this season before fulfilling a childhood dream by racing for Ferrari in 2025. Britain's seven-times Formula One world champion stunned the sport when his move on a multi-year deal was announced on Thursday. Hamilton, 39, said in a post on Instagram on Saturday that the decision felt right and reminded him of his move to Mercedes from McLaren at the end of 2012. "I feel incredibly fortunate, after achieving things with Mercedes that I could only have dreamed of as a kid, that I now have the chance to fulfil…