mybat, yoshi: I am guessing that she is probably either an only child (so far) or yoshi’s oldest.
I had the same thing with my oldest children. I was very strict about no sugar, but once they reached school-age, you can forget about that! Between birthday parties, Shabbos parties, siyumim, and alef-beis parties, the kids have so much sugar available, all you can do is try to teach them moderation. My younger kids already had the sugary stuff available from their older siblings, so I have taught them that it is for special occasions like Shabbos or whatever.
yoshi, am I right? 🙂