All those kickboxing movies lied to you. You don't get in good shape in 3 months, gear or no gear. But assuming you are already in pretty good shape...it depends. The steroid cycle alone will be 12 weeks. Plus, you'll probably want to cut after that. And if you're going on holiday, you want to be done with your PCT by then. At least I would
So...a good time to start your cycle...now. Yesterday. Last week.