There is no specific time to become a trader because trading is a constant learning, every trade you make you learn something from it. You can start right a away but do not expect much at first since all trader started from scratch so its expected that you are still experimenting just keep on trading and of course study everything about trading you will eventually be a good trader. Always remember that Practice Makes Perfect.
Yeah , Every trade is a new learning and regardless the time as long as you have a perseverance and patience in your trades because that will help you more to be a good trader . In no time also you can be a professional trader more experience learning and skills .