Unlike Type II (formerly "adult onset"), Type I is not related to health or diet issues like being overweight, and as my sister loves to point out, is NOT from "eating too much sugar". It is an autoimmune disorder where the body attacks the insulin-producing cells of the pancreas.
One thing that happens when first developing Type I is that the level of sugar in the blood spikes -- I mean, really soars, because the body no longer produces any insulin to break it down. I'm talking 8 or 9 times the normal pre-meal level. This will cause behaviors like fatigue or listlessness. If it stays that way long enough, deposits in the urine called ketones will develop as the body tries to flush out the extra sugar, and you'll notice a strange fruity smell. You haven't mentioned any of these symptoms in your daughter, which is defintely cause for hope!
Keep us posted!