(cut for spoilers, not that it's earth-shattering)
Zoë anticipates her Dad would "go nuts" should she come out, and her Mom "just wants me to be happy". Not really the way things worked out in reality... her Dad has been wonderfully supportive from the very start, and it's her Mom who's dug in her heels. (Granted, her Mom is being like that out of her imagination that transitioning isn't ultimately good for Zoë's happiness, but still.)
It's a good point - we're often dead-certain we know how our fears will play out, but people can totally surprise us.