There is mold on all my windows what is it from?

not to worry my friend it is no problem........................................... if it is on the out side if it is on the inside look around the window sill if there is mold there it is just leaky and you might need to replace your wall but if it is all over your wall especially in the joint you might need to tear down the wall but call a professional first I'm only 14 but i have a great understanding of things