Would it be easy to make this dress?

Making a dress to look like that would be challenging. You'd have to find fabric similar to the kind used on the original. Plus the techniques and sewing to give the same look and flow would have to be mimicked. If you have made dresses before, go for it, but it also may take awhile. Look at brands like La Femme. I was looking today at dresses and I saw a couple similar in color and style. Also check out prom dress search sites like cbslimited.com.