Circles in crochet aren't circles at all; they are a mathematical growth spurt and depending on the designer, the circles can appear more circles by a simple trick.
In most designs, the circle is growing at the same spot. While the circle is small, it's harder to see that it will eventually be a flat-sided object with the growth being at the same spot. As the circle gets bigger, you will see this develop naturally. It's not you, it's the execution of the design. In tutorials, this format is much easier to teach.
If a designer truly wants a circle, they have to change the execution to remove the growth in the exact same spot each time. Instead of the growth being in the same position, they have to stagger the growth to a different position. This confuses the circle and the crochet work will look more rounded.
Eventually, though, the circle will appear to be flat on the ending again and look more staggered in growth as the circle gets bigger. The circle needs to be broken up into more parts. For example, the circle below goes from 12 points to 18 parts to help prevent the sides from really flattening up. However, even below you will get the flat sides again as it grows out more.
Staggering the growth and adding more points so the growth is broken up into smaller sections will keep it a circle.
You Can Confuse the Crochet Project To Be Circle Too
Throwing in rounds like 8, 9 and 10 into a circle breaks up the incremental growth and changes the structure and stretch of the project. Usually, when I want more increments (points) to happen, I will put in a few rounds of something like below to allow me to easily change the counts and break up the circle into more parts.
Showin in green and pink near the centre of the circle below.
For me, it's not uncommon to start at 12 points, then to 18, to 24, 30, 36 and more. I usually try to keep it in an increment easily divisible by 6 or 12 sts.
This technique is also great for hats to stagger the growth so the increase spot isn't at the same location to be easily seen.
Have you completed this project. Show me!