The two most striking things I found moving from the 152 to the 172N were the heavy elevators (compared to the 152) and the tall instrument panel. At Vy the coaming is on the horizon, if I remember correctly, and it is strange not to be able to see forward when climbing if you're used to the 152. The most annoying thing about the aircraft is checking the fuel strainer drain in preflight - how is anyone meant to be able to reach the lever while holding the cup under the drain port?
On the bright side, I found the 172 a lot easier to land well than the 152. The version we were using had the 40° flap, which helped with short-field landings anyway.
As Dave says you'll have the instructor to point out the things to look for. and given the variety of different types you've flown, you'll be fine
I haven't had an opportunity to fly the Zenith, what is that like?