I depends on the person and the market. If you do it full time I know guys who do it in 6 months. However most guys will take longer or never make it at all.
You know the story of the Zen novice. He went to see the master and asked how long it would take for someone like him - a hardworking, determined intelligent person- to attain satori. He was prepared to give everything he had. The master said maybe 15 or so years. "But I mean EVERYTHING, I will endeavour night and day." Master: "I see. In this case 30 or more years."
You can learn very fast but you wouldn't know it. You need at least one year to tell how good did you do. Let's say you make 100% for the first six months of your day trading - this wouldn't mean much becasue be the end of the year you could give it all back and those 100% won't change the fact that you made no profit for the year Of course I wish you all the best in your trading