Yeah I write shit all the time, ideas and anything that I could think of. I've started a couple scripts and just fuck around, it's always cool to do. It does take a long time to make a full-movie though, it's over 100 pages of script. That could and probably will easily take at least a couple years. Then after you got a script ready to go, you gotta cast people. And then filming is hella expensive! For like a minute of filming it costs like 100 dollars or some shit, plus the equipment and everything.
But you gotta start somewhere, good luck with it...