First of all - congratulations!!
Sizes have always been a mystery to me although I'm starting to learn that so much has to do with body shape, height and body fat %. I hear people who weigh 200 lbs. wearing a size 14 and I was a 16 at a much lower weight than that. And I know people here who weigh about the same or more than me and are two sizes smaller.
So just fyi...I am now usually a size 8. That's the size I start with now but I don't cry if I have to buy a 10. Sizes are so different store to store. I've never tried on anything smaller but I tend to buy my clothes too big. I hate when my clothes are tight since it brings back memories of outgrowing my clothes so I think I unconsciously gravitate toward clothes that are still a bit too big. I'm working on it!
I don't know if this helps you or not!!