Why wait? Do it now.
I've always loved this. I go to it a lot when I'm thinking about whether I should enter something because my training isn't where it should be. I generally have over time gone and done that thing I've been undecided about doing anyway.
I've learned that I love the chase, the uncertainty that I might not make it to the end of something far more than the certainty that I will.
We are all different I guess but if you're thinking about whether you can, whether you're entered or not, don't say no because you think you're not good enough. Believe me you are.