A mirror does not give a reverse image of your face
A question arose recently asking why does a mirror reverse the image laterally but not vertically? In other words it appears, as you look in a mirror, that your ears have swapped sides, whereas your chin is still at the bottom and your forehead is still at the top.
The answer is that the mirror doesn’t change anything.
It is a mistake to think of the image as you, facing yourself. A real person looking at you will see your right ear opposite his left ear. True? But the right ear on the image is directly opposite your own right ear. It hasn’t swapped sides any more than your chin has gone from the bottom to the top of your head. Stop thinking of the mirror image as though a real person was looking out at you through a window, but see it as a reflection of what is really there.
It is the same with the mirror image of the written word. The reason emergency vehicles have what they are e.g. Ambulance, Police etc. written backwards on them so you can read it in your car’s rear view mirror has to do with the fact that they are behind you. The A in Ambulance is still directly opposite the A that shows in your mirror; it hasn’t swapped sides. The problem isn’t the mirror, but the fact you are reading a word that is behind you. I once worked in an Air Traffic Control tower and staff there wrote on a Perspex screen with chinagraph pencils. In order that people on the other side of the screen could read it, they wrote backwards, an acquired skill, fascinating to watch. But it wasn’t a mirror image, only that they were writing from behind the words, the same as you are reading words behind you in your car mirror.
There really isn’t a problem here, if you think about it. By the way, I once was punished with the cane at school, as an 11 year old, for arguing with the teacher that a mirror doesn’t swap things round, but then I did have twice her IQ…and I still have an axe to grind on that one.