The answer to this question is two-part:

1. The psychological aspect: Let’s say you are. Then what? Is no preparation a better alternative? Wasting these 4 months without giving it a shot and waiting for one more year, if that is something you can afford to do, then well and good, drop the plan. But if you are not dropping the plan, then asking this question is useless, and though you might not be late yet, if you keep dilly-dallying with your preparation with this doubt in mind. you certainly will be late. Also, if you start with this doubt in your mind, sooner or later the doubt will prevail and your motivation will be thrown off the rails. Being ever too consumed by this question is counterproductive. It may reduce your productivity from 1x to 0.5x. So, thinking about being late can do more damage than being late would. Stop worrying about it and start studying. 
2. The practical aspect: Let’s say a student, Fodu started in January and has been fairly consistent in devoting 2 hours a day to CAT Prep. In 10 months, he devotes 10*30*2 = 600 hours. Now, if another student Chhodu starts now and wants to invest the same number of hours, he needs 600/120 = 5 hours a day. If the latter resolves to put in these many man-hours a day, the two students are at a level-playing field. Moreover, my experience suggests that at least half the aspirants start their preparation in June-July, and that there is no bias in selection rates on the basis on when an aspirant starts. Every year I see many who start in July-August and perform brilliantly. But yes, there is one crucial difference between early starters and those who are starting now: the former could afford a little time to waste figuring out what to do and how to do, while the latter don’t have that luxury now. Therefore, it is advisable that you prepare under professional guidance, with a mentor who can help save those crucial hours. Stop worrying, start studying. All the best.