If your joists are perpendicular to the house then run with it as that would be the best way to do it!

Haven't framed it yet, but would like the joists to run perpendicular. Thanks for the support!

Instead of mitering the joint at the turn, you might consider staggered butt joints. It's a neat look, ( kinda herringbone), and lessens the chance of gapping at the joints that mitering is notorious for.

T&G should run in the direction of the slope, not against it. Your porch floor should slope away from the house to drain wind-blown rain (or snow melt) away from the house.
Perpendicular floorboards/house wall orientation is traditional for good reason.
Casey

Since it is covered and assuming you are in Texas with lower rainfall averages, I think running parallel would be fine. If you wanted to be anal about it, you could knotch out the tongue every foot or so about 1/2" long or so as drainage ports, but I don't see that as being necessary.

Sierra, you hit the nail on the head - pun intended of course. Thanks for tip on the corner. That could be a good look.