This is definitely super simple. You just need to be able to cut fabric and sew a straight line. It is that simple!
I bought this dress at Ross a few weeks ago for $3! I wasn't crazy about the skirt part of the material, but the more I look at it, the more I learn to like it! I took the whole dress apart so I could resew in a thinner piece of elastic. I just cut the elastic in half. Unpicking took longer than sewing, so I would say you can get this done in 30 minutes or less. I am speaking from amateur sewing skills too!
My skirt is a little too big, but eh, that's alright! I'm too excited to care. Maybe I'll fix it one of these days, but until then, I will just belt it.