First of all, you should identify whether you are interested in cycling or not. This is the most important aspect because if you have not a passion for becoming a professional cyclist then you will not be able to get there where you want to be.
Start participating in amateur level tournaments which will help you to evaluate your skills and potential and you will also be able to rank yourself among your batch fellows. It will also give a boost to your confidence which is essential for becoming a professional cyclist.
You should find a professional coach because you cannot become a professional cyclist without getting coaching or proper training from a qualified coach.
A qualified coach will help you in drawing a proper training and workout plan which will help you to gain strength and you will get required fitness to become a professional cyclist.
You need to follow the instructions of the coach and put in extra effort in training sessions because hard work in training always help in elevating the level of an athlete.
Make sure you take every training session seriously and try to give your best shot which will help you to gain higher level of fitness required for a professional cyclist.
Join a team at college or university which will help you to participate in different competitions. These competitions will help you in getting temperament which will teach you how to deliver a good performance even when you are under pressure.
Joining a team will also give you exposure and people will start knowing you as a professional cyclist. Always try your best to participate in every event which will help you to get practical experience and you will learn the advanced skills.