Sounds like target fixation....
You're getting to the point where the difficulties seem to creep in. I was told you need to make a decent final turn at the right height then keep speed and attitude right.
What you are looking for is the point where the green of the grass changes and you can see individual tufts of grass. That's when you ease back into the hold-off.
It might be worth asking your instructor to fly the next approach and landing and observe the visual clues for yourself. Too often the pressure to do it all yourself means that you don't get a chance to observe.