If you were getting it on your chest, would you get it facing you? It'd be pretty clearly upside down if you did that...
Another way to think abut it: if you had a ring with something in the middle, say a crown or something, would you wear it so the crown is facing up or down when your hands are at your side? Your body has a definite top (head) and bottom (feet) and tattoos look natural on the body when they're oriented accordingly.
It says in Galatians (not sure where) it says that Leviticus was the rules and word of man, not of God, so you're good.