I believe you have been searching on the internet about "mewing" and are reflecting on your overbite, but rest assured that you are not the only one who has an overbite and you can be sure that much of it comes from genetics. I also do not deny that stuttering can may have influenced us to breathe through our mouths while stuttering or kept our tongues in bad positions and ended up affecting our appearance and bite. But in any case, know that at some point you will stop worrying about it, there was a period in my life when I had low self-esteem due to the overbite, but eventually this sadness passed because the overbite is normal.