So I'm new to mewing and I would like to improve my nasal breathing, facial symmetry and jaw - cheek appearance. From what I understand the goal is pretty much to increase intramolar width on the upper teeth with proper tongue posture etc. Since I had braces when I was 17 my teeth are now straight and fit correctly with each other when I bite. (I am now 32 years old). My concern is that if I widen my upper patella and increase the distance between my upper molars won't my bottom teeth stop fitting correctly with my upper teeth? Is there some chain of events that takes place that somehow aligns the bottom teeth with the upper through the process of mewing?
At your age, expanding with the tongue will likely result in movement that is slow enough as to allow your mandibular arch to stay in balance with your maxillary arch. I recently shared my 10 mm expansion that took place between 2016-2018 (ages 24-26). As you can see, both arches have expanded in unison: https://imgur.com/a/SXIQWLi