So far, I have purchased seven of these ~ some for me, some for my mother.
The first batch, if you will, I ordered a size medium. I am 5'7", 120'ish pounds and roughly a 34B (umm, that's with a padded bra). The medium is definately true to size, and of course there is the spandex. So it's not "tight", but rather a comfy snug fit.
So here's the thing...
My most recent purchase was four more, but this time in a large, just out of curiosity. Lo and behold, the large [in two of the shirts] was the exact same as the medium. And while the shirt BODY is longer length and great for tucking into lower rise jeans, the sleeves, on the other hand, just aren't long enough. I do have long thin arms, but I HATE having to constantly pull the cuffs back down OVER my hand. That is the type of longer sleeve shirts I like. Seems Old Navy USE to carry that style, but no more.
As a further comparison, I held up each of the new size Large shirts. The sleeve length varied in each and every one. Some longer than the body, some at equal length.
RECOMMENDATION: you have the info, so read other reviews and purchase at will.
WHAT AM I GOING TO DO? I am using cuffs from the size medium shirts, flipping them inside out and using the "stitchless glue" [yes it works, it's great, permanent and comes in a tube at Joanne Fabrics, etc.] to elongate the sleeves of the size large.  Crazy, waste of money? Eh, just a short term fixit for me.
I have NOT washed anything yet, but in reading one of the customer reviews I MIGHT just hand wash these in cold water and let them air dry....??