Jake (and others) have made some good points that deserve to be highlighted...
If this is your first studio you probably have much to learn about studios and music production and most important - music production in your studio. Don't aim for perfection - it is the enemy of good (I think that's the quote?).
Aim to have fun making music you enjoy and work towards your next goal from there. Which means you don't have to sweat the details of the room just yet.
Second point - there are no concrete rules of formulas or tricks - some loudspeakers want to be placed against a wall, some want to be placed IN the wall, and some want to be freestanding. The trick is to use the approach that works best for your monitors in your space. Experimentation is your friend!
And third - while I would not want to mix exclusively in headphones, don't overlook them as another tool! And if you can swing it a second set of monitor loudspeakers won't hurt either<G>.
One last thing - please be aware that room correction software (Sonarworks, IKMultimedia, Genelec, etc) does not actually correct the room, or even the room response. It corrects for problems it detects in a single point in space. Anything more requires adjustments to geometry and (sometimes) mucho treatments.
Don't misunderstand - while I am saying that it is, in the larger sense, an illusion it can be a helpful one. If you accept that it is correcting room anomalies at your listening (measuring) position, but not necessarily the entire room, you'll be fine.
Room correction software can be helpful, you just need to be aware of the limitations.