If you think that you are not going to excel into something, it's a good decision to stop. But remember, even you stopped you can still get back to trading again whenever you want. Because I experienced that I wanted to stop but I hold on and right now it's a good thing that I didn't quit trading, because the price is increasing.
Generally people make decision of quitting trading once they have made loss from it but they forget that profits and loss is a common practice in trading and even if you make loss you should not be disappointed and take it as a learning experience and make sure that you don't repeat the same mistake again in future.