1300 Calories a day..Is that ok?

Im 22 years old girl & am nearly 5'2 tall..
I weight about 120 lbs
For the past 2 weeks i've started taking in a maximum of up to 1300 calories only..
is this ok?
i want to lose about a stone..will this help?
I eat breakfast lunch & dinner
i've cut out chocolate and eat fruits..