when you say you dislocated your knee - do you mean your kneecap, or the entire knee joint. From the timeline you're stating, it sounds more like the kneecap?
I suspect your plan is based on advice from a doctor/trainer/etc of some sorts? Honestly, thats the best place to gauge when to return to sports. I would think if things rehab/heal correctly, you should be back playing this year. Work with your PT, and don't rush it, rehab it right the first time, and it hopefully won't happen again. Everyone heals differently, and the 'normal' timetable would depend on the severity of dislocation.