I suggest you watch your instructor in your peripheral vision. When he twitches, it's time to flare, not before.
Seriously, we used to teach flying on grass airfields for night flying (RAF), with only edge lighting and no white ground markings to see; the visual effect was that of landing in a black hole in the ground. The method taught was to wait until you got a feeling that the edge lights were coming up around your ears.
I suggest you wait for a quiet time, taxy out onto the runway and sit there until you can really visualise the sight picture of the aircraft on the ground. Then go and fly some more circuits. Get your instructor to demo some landings and use your peripheral vision while he lands.