A couple points.
1- You've got to ask yourself.. can I REALLY manufacture this?
2- If yes, would it not be easier to just weld that ~4" wide top section [curved] in rather than trying to break and form it all in 1 pc. I realise this is just a light 14ga pc of metal but.. it does beg the question..
3- All sheet metal sections which are curved like your top curve there, need to be tanget to some line at either end. [I've changed your model to reflect this]
4- Typically modeling in this process [what we call the 'old way'] is done the same and then it's 'ripped' to open the edges where we want to weld so that the box can be unfolded. In this case however w/ the curved wall and various other nuences it's much faster to just do two cuts which create 'rips' and they will also give you a much cleaner joint rather than a corner fillet. W/ a little flap disk sanding you'll have a nice sqr corner rather than an exposed fillet joint on the corner/edge.
Sheet metal is a fun tool to play w/. It takes a bit of testing and messing to get used to it.. in time it can be a very fast and powerfull tool.