But what's in your head will change as you grow and change, and if you're really lucky you will never stop changing.
Ooh, with small limits the thing to do is cram as much goodness into that space as possible. It's only easy if you let it be easy, there are people who restrict themselves to a certain word count as part of the challenge.
Good luck, with prose or poetry or whatever.
Lemme guess ... Sex, drugs or rock'n'roll?
You have it and you could post it, but you don't because you don't want people to see it before it's ready to be seen, do I have that right? But that's all of writing, nothing is perfect; if you keep it to yourself until it is "ready" you may never post it at all. I post things online because that's how I might be able to get editing and peer critique, the things that will make it better or even maybe "ready." And the better I get at writing, thanks to people responding to my "unfinished" works, the more "ready" my fresh work will be. The cost of learning to write may just be embarrassment.
If you're still unsure, you could share it with me privately via Stash. I might even have a piece or two back in my gallery to rival it.