I said yes to the dress today!! I am on cloud9 right now!

however, I am slightly stressed! After I chose my dress, the lady took my measurements and my chest was perfect for a size 8, but my mid-section was exactly between an 8 and 10..so the woman made me decide which size I wanted her to order. I told her to order a 10..but now I am doubting my choice. I have been working out faithfully and eating very healthy and have been losing weight. I am planning to lose another 15 pounds before the big day which is in November..so do you think I should have went with the 8? (my dress is a corset back - incase that effects your opinion) Thanks in advance for your thoughts!