I am finding it hard to land my trainer. It is a frontier 40 with a thudner tiger 42 ( i think, could be 46?)

I get the motor at complete idle and it still does not want to come down, unless i am nearly forcing it to the ground!

This is my first plane and i have no idea on what prop size it is.

Can anyone suggest a prop size. I am going to my local HS over the weekend and can grab a new one, the guy there doesn't know much abotu planes.