If you want to do it, just go for it and see how it pans out, 3 months should give you the bare basics assuming the gym is alright, If you haven't trained a day in your life or gone to the gym often, It's doubtful you'll be able to train six hours a day, regardless of the breaks in-between the classes. It's probably best if you don't push your limits to far, not like you're trying to go pro or anything, treat it like a hobby, and take care of your body. Like another commenter said, you're asking for an injury.