Why do i keep sweating????? ?

I know sweating is good for our health, but my body would sweat even if the weather is cold or when i am standing still example at school, shopping mall and etc, some people said i am fat that is why i sweat a lot but my little sister is almost the same size as me but she doesn't sweat that much, while playing badminton every sunday after 2hour of running and jumping my shirt would be so sweaty, so sweaty that i could extract the sweat out of the shirt by twisting it and that is just too gross and that isn't normal because i am the only one in my family that is so sweaty, so y am i keep sweating?????