White: mate in 3 – position possible?

This is a puzzle I created. If it’s not cooked, I consider a very good one, for I never saw anything like this before (did you?). Take a look on the surreal situation that takes place:

White to play: mate in 3

I’m  submiting this topic not olny to see if it’s cooked (if it is, can it be mended?). But also, to see if  this position is possible to be reached in a real game. Notice the black Bishop on c8 – it didn’t move to there (what would be impossible), but, as it is on its initial square, it actually did not move all during the game. About the pawns, help is needed to know exactly about if they are possible to be there. And finally, if it can be improved. Thx!

First, the position is legal, and it's simple (but tiresome) to reach it.

Second, looks okay for me, but I'm not good in directmates so I can't say with certainty.

oh, thx for the game you created above and comments! More than theories, It proves, once for all,  that it's a legal position. A hard work, I don't know if I would be able to do it, so, lots of thx :)

NICE

is this practical!??

If not then what?