That said, there are some girls who start their pubertal changes a little differently. Most girls have breast development first and then they develop pubic hair, underarm hair, and odor. But about 10 percent of girls start with the hair and odor first, and the breast development comes a little later. It is not clear why this happens, but it is a well-described pattern. It is possible that your daughter is beginning her pubertal changes this way, but it doesn't mean that it is premature. Remember that some girls begin their menstrual periods as young as 9 (the range is 9 -15 years old), and the early signs of puberty start about 2 years before the periods start, so seeing changes at age 7 is not necessarily abnormal.
There are certain abnormalities of the adrenal gland that can cause the body to sweat more intensely, but they are very uncommon. It would be reasonable for you to make an appointment for your daughter to see her physician. That way you can express your concern, and she can be examined to assess whether or not there are any early pubertal changes.