The short answer to your question is no, not necessarily. Sweat glands do develop and mature in response to certain hormones in the body. These hormones are produced by the adrenal glands, which are in the abdomen, just above the kidneys. Some children will have early maturation of these hormones, without the other hormones for puberty turning on. This is called premature adrenarche, and is not uncommon. It does not mean that the child will go on to have premature puberty, and it is generally of no consequence. The other sign that you see with premature adrenarche is early development of pubic and underarm hair. However, unlike premature puberty, there is not any breast development and the girl does not start her periods earlier.

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.