[michèle 2]

This morning during my adult one to one class we came across the following example in a conversation.
He's having his first lesson today. He's going to the driving school at lunch time. He's really excited about it.
My student asked if she could say " he's really excited about that"
It refers to "he's having his first lesson" Does "that" refers to the previous sentence I mean "he's going to the driving school"
Is there a "rule" for "it" and "that"
thanks for your help