I've screwed up worse than that before now, and suspect so have most other people around here. The important thing is not to commit the same mistake twice.
My personal solution to this is to have the relevant Pooleys page in my kneeboard, and draw the approach on in chinagraph once I've been given join details. Works well, although occasionally I'm known to remove the card and orient it with the world outside the window to reduce the strain on my grey cells.
My regards to your CFI, I like his attitude and approach.
G