Don't worry about it. Most people have some sort of size differences between their left and right sides (feet, hands, boobs, leg length, etc.). It's not uncommon at all.
I first discovered this when I was a figure skater when I was a little girl. One foot was a 1/4 size bigger than the other, and because the skates were so precisely fit I had to order two different sizes. In fact, the skate mfgr. didn't sell them in pairs, only singly to account for size differences.
As an adult I notice that my left breast, my left rib cage, and my left foot are all slightly bigger than their right side counterparts. It's not noticeable to anyone else (except to my physical therapist when he was trying to see if I had a hip problem and was wondering why my measurements were off), including my DH.
If it really bothers you you could practice standing with the right side more forward than the left (since if it's closer to the other person it may appear bigger). Just a thought...