How do I change the health at the start of a quest game, in 'Text Adventure'?
If you are using the health feature, you can't. The first time the player takes control of a certain character (including at the start of the game), their health is forced to 100.
I would suggest disabling the "health" feature, and just give the player object a health attribute yourself. Alternatively, you can change the player's health in your start script, which should run after it's been reset to 100.