How can I reach upto Olympic level competitions?
There's no way we can answer this question for you. The people who reach elite-level competition in cycling have extraordinary natural gifts, dedicate enormous time and effort to training (20+ hours per week), and are incredibly motivated (to train intensively for 20+ hours per week, etc).
If there's a local cycling club you can ride with, do that. If there are any races in your area, enter some races. See how you like racing, and see how you do. Start reading up on training methods and learn what you can. Usually the people who have those exceptional gifts rise to the top pretty quickly, but even if you don't, don't let that discourage you from having fun with racing at a local level.