Some would say that you are expecting a bit much. You are flying in from one of the busiest directions essentially straight over Tullamarine into Essendon only a few short miles away. Your descent would be right amongst the busy stuff. Where are you planning your descent into Essendon? 5500 is irrelevant isn't it because you would need to be below that over Tulla?
5500 is probably not high enough for a transit either and not being IFR doesn't help either. I was told I needed to be above 6 to get over Tulla, let alone descending into Essendon. Try tracking around to the North east near the VFR lane and entering Essendon from near GTV or alternatively via Melton to West Gate. There is more to learn for a student and more chance to demonstrate their skills remaining OCTA to the west of Melbourne versus finding and overflying one of the biggest airports in the country into Essendon - not much of a challenge really. I'd take a PPL over Tulla and a CPL via the outskirts because anyone can fly in Class C with the big boys without too much effort.