And welcome! To answer your question, the difficulty rating is to do with how difficult it would be for your player to win the game. So, if all the paths led to a winning ending, that would be a 1, but if you had 1000 different possible endings to the game and all of them led to your character dying except for one, that'd be an 8.
Welcome to the site ! Making pages is great, but make sure to fill those with a great story. Good luck in your project !
Welcome to the best interactive fiction site, I'm glad you're having fun!