Alterations to make maxi dress into skirt

I love this Liberty for Target dress I bought probably five years ago, but it makes me look pregnant. I would really like it to be a maxi skirt instead of a dress.

So - shortening the dress into a skirt. I'd like to keep a ruffle at the bottom. I'm not so attached to the smocking, but would prefer that waistband makes the fabric sit against the hips a bit rather than poofing out.

I've attached a photo of the dress as it is (the blue and floral), and then a general idea of what I'd like it turned into.

The dress - 100% polyester, lined.