Hi
Start worrying when you have a total of 30 hours of instruction. Don't rush things, flying is expensive and you are wondering where the money is going
There is some wisdom in what Big Pistons has mentioned.
I mentioned in another thread the use in the USA of ground reference maneuvers including rectangular patterns, turns around a point, and s turns along a road.
And perhaps you are just destined to take more time to learn than others.
Someone mentioned walking a circuit (pattern in the USA), you might try drawing the pattern by memory on a piece of paper with pencil (do you know what a pencil is?)
So, it takes time, MONEY, dedication from you to IMAGINE it on the ground.
And you might consider another instructor if you are not learning.
Again, some people have soloed in 4 hours, others 40. You will probably be somewhere in between.