Those who must make their own mistakes to learn are already behind those who can learn from others' mistakes. By all means, jump in quickly, fail early and fail often in order to learn something, but recognise that there will be others who take just a little bit longer to get in and will figure things out just as well as you have. Unless you're doing something truly new and original, other people have already learned some of the lessons you're going to learn through failure. Take some time to find out what they are.
Mokalus of Borg
PS - If you're absolutely certain you're doing something new, that's usually Mistake 1.
PPS - Usually, but not always.