The most likely reason is that you chew unilaterally for a long time. Another reason is that when I was a child, the mandible was traumatized and developed asymmetrically on both sides.
Now the situation is more serious. The center line is uneven 1 tooth or more, about 5mm or more. It is difficult to correct this situation simply by orthodontics.
Now I suggest you go to the hospital to take a panoramic picture first, and observe whether the uneven midline below is caused by the unequal length of the ascending ramus on both sides of the mandible. If the bones are not the same length, surgery is needed to correct them. If it is just a simple dentition disorder, it can be corrected by orthodontics, but it may be necessary to extract teeth.
As a reminder, if the appearance is not particularly obvious asymmetry, or affect the function. It is best not to have an operation. The cost of this operation is not low, about 12000, and it is also painful after reading it. Besides, at the age of 23, your bones are basically shaped, and you can't change your shape by chewing.
I wish you a speedy recovery.