Please critique my posture

Hello, Alensa, thanks for your Tallstanding photo.

Lower Body: you have good softeness at the groins and knees, and your behind behind you:). I think work towards geting more kidney-bean shaping and lift in your feet

Upper Body: use shoulder rolls to help position each shoulder in turn further back, and with some external rotation - ie., so your knuckles face more towards the side than front. Maintain your Rib anchor position whilst doing this, and also while continuing to glide the head up and back - at present it drifts forward from your shoulder girdle.

But this is a great starting point - take things gently, steadily and consistently and you will see more improvements over the next few weeks and months. 

Yes, I think roller work would be a good technique for you and compliment the shoulder rolls well. If you are in the US then go for: https://shop.gokhalemethod.com/products/gokhale-roller

There is a very good video on the website on using it too.