It depends on what you want. If you would like to be pursued by men who don't much care about you for any other reason besides that they like your chest, it's fine. But this is why your mom is making the face. She is worried about you being used by men, or cared about as a trophy or toy. If a woman has something to exploit there will be men to exploit it, often women find themselves not in charge of their destiny when men get the horny attitude going. You'll also get your share of the side-eyed stares from women and catty remarks.
I've had smaller and larger bust sizes in my life, and had men stare at them and be really rude, like yelling "Wow" looking right at them on a public street. Luckily my smaller-breast sizes were when I was younger and would probably have found that kind of thing almost shaming. Having the boobs hit at only 16 can be kind of hard to deal with, partly because you don't really know how vulnerable you are.
The other problem with the bigger boobs is that when I have them I don't look as sleek in my clothes, to me I more resemble the prow of the Queen Mary, and the size of my bust makes me look more matronly, or even like I'm fatter in the waist even though I'm not. It's a proportion thing. When my bust and hips are about equal, I look and feel more athletic and slim overall.
That said, your body is your body, and there is nothing wrong with celebrating having luscious bosoms. Just keep it a celebration for the right reasons, they are for you to like for yourself and be pleased with as a woman, not for you to cut your shirts low and try to attract the wrong kind of attention for the wrong kind of reasons. Love yourself and keep your grounding, stay real and don't try to use them as a power trip, and you'll be fine.