1) Not having a plan benefits no one.
It is scary to have a plan. Making a plan predicts a certain outcome. When it comes to publication having a plan means either dealing with success (whatever that word may mean to you) when it comes or facing the bitter eventuality that this career is not for you after all. It is easy to write. It is harder to set goals, stick to them, and refine or change them when the results are not what you wanted.
2) There is nothing to be gained by being fearful.
Seeking publication is frightening. There is a fear of being judged for what you write. The fear of rejection. The fear that you aren't as good as you think you are. But not doing something because it might turn out badly guarantees it won't turn out well. Taking risks means facing failure. It also means pursuing rewards.
3) We don't know what will happen tomorrow.
It is a particular flaw of many writers (myself included) that we want to take one last look at that story, let it percolate a little longer, tweak it just a little more. And then I realize I've been working on a short story for months and months and it's no longer getting better it's just getting different. No one wants to send a story out too soon, but there is no benefit from sitting on a story 'til you're dead.
In short, make a plan, then write (and send those suckers out for consideration) like there is no tomorrow.