Our rib cage is different, wider, than cis women, at least for most of us that is the case. That´s why the breasts are positioned a bit wider and looks smaller, due to the lateral positioning.
This bothered me too a lot. But then I started to look women on advertisement, newspapers, bikini pictures etc etc, where nobody is wearing a bra and noticed, that a lot of women have their breasts positioned quite lateraly and the gap between, is as wide as mine, if not even wider for some.
Every body is different...and this one is mine 🙂