Greenhouses, Sheds and Sun Rooms - double door. Help please!

I am just about done with my shed (finally) and am now on to the doors. I am using t-111 siding and 1x4's for the trim. my question is, if i am doing trim around the entire perimeter of each door, a horizontal piece in the center and an "x" design on the doors (all exterior), do i need any bracing on the inside? maybe 2x4's (or 3's) around the perimeter on the inside? would like to finish today so any help is appreciated. thanks.

You should have enuf, but it sure wouldn't hurt to run a single 2 x 3 diagonally on the inside from the bottom hinge side corner to the upper latch side corner. This would help w/any possible sagging. But you'd need to screw through the outside to attach it.
You could also leave it off and attach it later if you feel the need.

i'm also concerned about the lack of material to attach the trim and hinges to if there is nothing on the inside. should i be?