My instructor used to demand consistently perfect landings before he'd get out (this was after first solo). One day he was away and I flew with someone else; I did one good one, one passable, and one crap approach and go-around. He said; "I'm getting out of her; you know when to go around, so you''re safe". All instructors are different, and so are all students. Frustrating though, innit? I know how you feel. Don't worry; you'll get there in the end. Easy for me to say I know...but you will.
Good luck,
Whirly (48 hours approx to first solo, with two "false" solo checkrides; I didn't post on the thread; fed up with the fuss about first solo)