Hi so I'm 14, 5"7 and my weight is 112 pounds or 8 stone. I have a pretty fast metabolism. I feel like this is an okaii weight for me but am not that fit exsurcise why's. So what should I do to keep fit? Any ideas that actually work. Am not looking to lose weight am just looking to stay that weight I am but be more heathly. And also is 1800 calories a day good for me?