USA international midfielder Aaronson is joining Leeds for a fee of £25m from Austrian champions RB Salzburg in a move that will be ratified on July 1, subject to international clearance and a work permit.
Aaronson is still only 21 years old and the States star is excited by Whites players even younger than himself who are already excelling in Marsch's side.
The summer signing has picked out 20-year-old striker Joe Gelhardt and 19-year-old midfielder Lewis Bate for praise as Whites boss Marsch shows his clear faith in youth.
"It's very exciting," said Aaronson to LUTV,
"Seeing some of the talents that are coming through right now, it's amazing.
"You have Joe Gelhardt and Lewis Bate and a few of these other young guys that are killing it and they are doing really good.
"In the last games they are getting trusted by Jesse in huge games so it's exciting and it's great to be a part of it."