Aviatorklb brings up a good point.
It is very important when learning to land that you have a consistent seat position and in general the higher the better . C 172's, in particular have a range of vertical seat adjustment that will produce very different sight pictures. I tell my students to start with the seat cranked to the very highest setting. For shorter people I add cushions, but the bottom line is you should be looking down at the cowl top and the sight picture should be the same on every flight.
Interestingly large aircraft flown by professional pilots all have a "eye height indicator" device witch allows pilots to set a consistent seat height as they move from plane to plane in the course of the day.