To anyone searching for this, I solved the problem. I wasn't defining the body
that entered the Area3D as the player. Instead of:
func _on_enteringTheForest_body_entered(body):
enteringTheForest.show()
I needed to put:
func _on_enteringTheForest_body_entered(body):
if body == player:
enteringTheForest.show()
I defined player at the start of my scene as onready var player = $(whatever the name of your player node is)
Happy coding!