Translation:She is approximately forty years old.
Why is this in Weather 2?
Most likely that Duo is trying to teach you more applications of 大约.
I used "roughly" instead of "around". My dictionary says its ok.
Yes, "roughly", "around", and "about" all are ok here.
what about 大概?
I thought 岁 was only for low number ages (children). Is it really used for age 40?