Well done mum, I actually tried my wedding dress on the other day and it is two sizes too big, not bad considering I married 16 yrs. ago.
I think you should go and get yourself a size 12 dress to hang in the wardrobe. It is one of the tactics that I have used to help keep focus and it works for me.
I bought a size 16 leather jacket last year at the sales, at the time I would have been a size 22, I tried it on the other day and it won't be long before I can get the buttons done up. Pretty good considering when I got it I tried it on at home and then had to get hubby to almost peel it off me as I couldn't bend my arms and I didn't want to burst the stitching
So in short I say go for it.