It's not about knowledge you have in Forex but there are many factors that will definitely make you profitable. Emotion and risk management are some while it's very important that you have trading experience in the platform of any broker to know of the market.
There are so many qualities that make a trader what he is. There are even traders that would posses the same level of knowledge anyone would wish for but are not good in controlling other factors. Others can't just be patient enough to pass through the learning process while some others express high sense of anxiety.