I think there’s no specific time to learn all the coding or a way to learn all of it because it never ends, there are actually a lot of things you could learn but go to the basics… I guess it takes a while but not a lot. You can watch some youtube tutorials (I recommend you Joseph Evans and EllyT -something like that) or learn through the guide Episode has. Also, play with them. Sometimes while playing you can start doing advanced directing without noticing, whatever figures in your mind put in on the script and see if that works or not.
Now, talking about the story… Not everything is about coding, the plot is so much more important, so, if you have planned it and it is really nice it won’t matter how your directing is, all that will matter is how your story goes through!
Also, don’t let yourself feel intimidated by whatever thing people will say when you get your story out, stay with the good comments. There’s a lot of people that’s a bit trashy but don’t get them so much attention. Enjoy what you’re doing!
Edit: if you want to read my story, here’s is the link: http://episodeinteractive.com/s/6420401277763584