How much should a 14 year old "5.8" girl weigh?

Christine
Hey just wondering how much I should weigh. A lot of my friends are way lighter then me but I am pretty tall for my age so I don't know. I'm 5 foot 8. Right now I weigh 121lbs. Is that good? Or is that too much. I thought 110 or 115 would be a healthier weight but I don't know. Please help!