Gigi, here's my experience for what it is worth.
The tee stretches out a small amount when worn, for me, entirely in the sleeves where I scrunch them.
When you wash linen, you can "block" it, similar to wool. In other words, you can shape it so that it dries more or less the way you want.
Mine have not shrunk in the wash. I wash in cold water, machine, and lay flat to dry.
If you wanted to stretch it, you could hang to dry. If you want to make it a bit smaller, you can "block" and air dry.
You could also try it in the dryer, but that might shrink it too much; I'm not sure.
So sorry this may not work for you, but I still have hope.