@m1903, not a bad cut at all, but there's too much space between the bottom of the chin and the bottom of the cut. While it is true that collars are to be included in all cases, the focus should be on the face as much as possible.

In sources like this one, the person in the image may have a longer neck than usual and the above would be quite difficult to achieve naturally. This video & this post displays a simple technique of how to cut close to the chin and still display a bit of the collar.

I'll do it myself for this source, but do keep it in mind for the future