My first was actually pretty good--for an eleven-year-old--and not based on anything I had seen before.  It was 118 pages in length and I couldn't wait to get it copyrighted, which I eventually did.  Then, when I was eighteen, I took it out again and rewrote it.  It was much, much better.  Then a few months ago, I spent sixteen hours and rewrote it again.  It has a different arch, and different emphasis but it's still that wonderful first time for me.  Every script is a first time because every script is about something new.  I've received pretty great feedback from it so now I'm trying to sell it.  Wish me luck.