So the player can start in room one and have the choice to go to room two or room three. Say they choose room two. In the game, after choosing, both choices are still highlighted (even while the text from page 2 would show up normally) and players would be allowed to just go straight to room 3 from room 2, even if it isn't linked.

You could always just clearscreen before entering the room.
That way, the previous room, and links, are not visible.

How would I do that? And just to clarify, is there any place I could find (other than the basic and mostly-useless tutorial) all the codes for gamebooks? It would be very helpful. Thanks~

Nevermind, I realise what I was doing wrong and will try to remember from now on. Thank you!

Learning is full of mistakes...

Try going with Text Adventures...
You will learn better coding on something more powerful,
AND...
TA can do GB if you use one way exits...