Go ahead and give it a shot just for fun, Even if you dont end up posting an entry its still worth going for it as its good practise for the normal Jams that dont announce a theme until a little before the start.
I announced the theme early deliberately to give people like yourself a bit more time to plan ahead a game.
Although the game should be made during the game jam tme frame (usually 7 days), I felt this was too restrictive for people new to a Jam.

It does of course open it to people cheating and making the game before the start time but they only cheat themselves at this stage as when we do a 7 a future one it will have its theme announced later.

Hope this helps and if you are on discord its worth jumping on there if you want to collaborate with people :)

I moved the community game Jam channel to the top of the channel list so its easier to access

It depends really on the format of the game, I think for a download itch go with a zipped up build file so it self extracts but as long as we can get access to it then any is fine :)