So my pattern arrived today and I have spent a fair bit of time studying the back of it - especially looking at those measurements. Hmmn ... I think there may be trouble brewing and I don't know how to resize a pattern up three! sizes and based on my measurements (which stay fairly true when I'm not pregnant) the size 16 then is equivalent to almost a 12 now. Hmmn...what to do.
Dig out the dressmaking books and learn about resizing patterns - that's what!
After that I will cut out and sew up a muslin and compare it wish some of the muslin's I did for dresses I made last year. I might even take it to my aunt's place and try iton her adjustable dress form.
If I am planning on wearing it just a month after I have a baby - it shouldn't matter if the muslin is too big.
I think given how much I am in love with my fabric - I will put the pattern on hold at that point until post giving birth when I can at least fit the dress too me.