Just to make sure: it was only inside for the picture, right? If not, bring it outside to keep it healthy.
I would not prune it now. Growth depends on aboveground biomass. Let it grow for another season. It will get bigger much faster. Wisteria loves water during the growing season (and want to be drier in winter).
The plan you have now will end up in two competing trunks which in general is less attractive. I would go only with the left trunk but take tje first branch towards the right, to get a few curves.