I'm 34 and have personally experienced significant changes in my face thanks to orthotropic pressure / mewing, and have the photos to prove it.
In addition, my bite has been stable without a retainer, whereas in the past I've had braces twice.
My background is I had an undiagnosed mild tongue tie that I discovered a bit over a year ago. I previously couldn’t press my tongue against the roof of my mouth, which led to a tongue thrust on swallowing, which led to an open bite, and my nasal breathing was very constrained.
In addition, my bite has been stable without a retainer, whereas in the past I've had braces twice.
My background is I had an undiagnosed mild tongue tie that I discovered a bit over a year ago. I previously couldn’t press my tongue against the roof of my mouth, which led to a tongue thrust on swallowing, which led to an open bite, and my nasal breathing was very constrained.