Ideally I would write a paragraph text normally. Then I would use a script (or action) to make it take an ellipse shape.
The problem is that I don't know much about scripting in Photoshop, so I come here to see if you guide me. Manually I would do something like make an Ellipse (U) about the same size as the paragraph text. Copy the text from the paragraph. Paste it inside the shape. And then delete the shape layer.