Don't let anybody be too hard on you either way!
My children nearly always shared rooms. The first two - a boy and a girl - shared a room for a couple of years, until #2 girl was old enough to share that room with her big sister. Then Big Brother moved into the other bedroom, only to share it with Little Brother when he came along.
There was a little fightin' and fussin', as happens with all children. But they did all right, and respected each other's space - more or less. When they grew up and went off to college they all said the transition to a dorm was easier because they were already used to sharing space.
I, on the other hand, was one of two girls, and we always had separate bedrooms, and I had no objection to that!
Of course, when your two are older, they'll need separate rooms because they're separate genders.