Well, honestly, there is no straight answer to this question. There are many factors that make each trader different from one another – diverse strategies and approaches, different financial background, unique trading characteristics etc. Some trade aggressively, using wide stop loss settings and win big time. Some cannot afford to take such risks and work their way up slowly. Many are influenced by too much greed, therefore act irrationally and loose their money fast.
What you should realize that the most important thing in forex trading is the right perspective. When a trader stops seeking to profit as quickly as possible and sets the long term plan the greed is taken over the common sense and therefore the trader makes much less mistakes. By giving it enough time and training even an average trader can become profitable.
Don't think of trading as something you can do overnight. This is possibly one of the hardest 'professions' to 'qualify' for. Be ready for some sweat and tears because when forex starts to work for you it is the most satisfying profession in the whole universe!