Sorry if dumb question

Is black allowed to castle on move 13, while my bishop is threatening through the castle?  This is from Live Chess.  I thought it wasn't allowed, but must be wrong.   Thanks.

Yes, since it doesn't matter if the rook jumps over a threatened square. It only matters if the king does it. The king must not castle in, out or over check. No one cares about the rook.

Yes, you are not threatening the king, since no check and you don't attack c8 or d8, only squares by which the king passes.

Yes black can castle if he wants, it is only the king that can't move through attacked squares and since the king doesn't move through the square b8 castling is legal.

The King is the only piece during Castling which may not move through an attacked square; the Rook may safely move through this square, as long as the King does not land up on or pass through an attacked square.

Nice Queen's Boden mate though. Black's castling obviously worked in your favor.

thank everyone for responses ... I learned something ;)

 That's the whole point of Chess.com, isn't? :)

indeed .... and this is a great place for that