Is it ok to eat less than 1200 calories a day if you're a teen?

Is it ok if you don't exercise (AT ALL) for the whole day everyday and eat less than 1200 calories? I usually only eat 700-800 calories a day, is that enough? I feel really full just eating 700-800 everyday, and sometimes I force myself to eat up to 1200 even if I'm really full. Is it ok if I eat less? I know that eating less than 1200 puts your body into starvation mode and all that, but I don't feel hungry anymore. Is this ok? Or is it still bad for my body? Thanks. :)