It is from Crash Course US history. It is at around 30 second. Here is the context:
Mr. Green, Mr. Green, if it is really that simple, I am so getting an A in this class.
Kindly note: in the past 15 years, more or less, so has started being used in place of "very much".
I will very much [so] be getting an A in this class.
He is very much [so] going tonight. [meaning: he is very much going tonight]
Nowadays, "so", an adverb (not when it is a conjunction or used to start speaking),is used to emphasize verbs. Some of this is traditional:I so want to go. [I want to go so much.]
But, when it precedes a verb as in "so going tonight"; "so doing that"; so liking this", that use is not traditional and young people use it all the time. It would be considered informal register.