Konoha is 48 Years old.
Sandaime was born in 56BK, Konoha was founded in 48BK by Shodai and Nidaime
I had a time line project a while back here on the foruns that gave with more or less precision the dades.
All dates were based onto the firsts databooks. And I stoped since that time I had just some of the translations of the dates etc.. I might consider come back now with more info
Btw, for all there..
SHODAI (First hokage) Shows up and CREATE konoha, if you don't know he is the "original" Yamato.
He have the power to create trees.. with that power he created konoha, the place could've been a desert for all we know.
"Chile is a thin and tall country"