If they are referring to physical size then you would have encountered problems well before now if the ventricle or valves were too small. Children born with small left ventricles/valves are in serious danger because the heart cannot pump sufficient oxygen around the body. I believe your ventricle is still too large for that or you wouldn't be here. Your systolic function has no problems, and you are obviously getting sufficient oxygen around your body, so I wouldn't be concerned about it.
As fas as I understand, it should not give you troubles.
Jesus