You've got one of the most experienced, if not the most experienced surgeon. you'll be fine.
46 probably refers to the femoral head diameter in mm. If I recall correctly, I have a 52 mm cup and the wall thickness is about 3 mm (2 times), so I should have about a 48 mm femoral head. I'm a slightly smaller framed male. The reason you get the sense that there might be a threshold size of component for women or smaller framed people is because there are some surgeons that won't do smaller hips with MoM because of the concern for failure from metallosis. Less surface area = more friction and more wear,....I don't know where the cutoff is in size, but you're well within the standard range. Also, there are many smaller women that have excellent results, which is likely due more to the experience of the surgeon than the size of the component.