Ronie-MayTee, I myself got cellulite at about that age maybe even at 14...cellulite effects alot of women even those with legs like sticks. It is a result of water retention and has very little to do with the size or weight of the person. I ave recently been on holiday and just realised how many women really do have it, the statistics are right!
You can aim to reduce cellulite by:
Drinking plenty of water at least 2 litres a day (reduces the toxins)
Avoiding caffiene (chocolate, coke, tea, coffee etc).
Using a natural body brush in circular movements all over affected area before showering.
Increasing excersize often helps so give it a try.
There are also some creams/gels available although there is a flaw in that it may just be the rubbing it in that causes it to reduce so some say you may as well just do the same motions but with an ordinary moisturiser.
I'm sure theres other ways as well but these are the best in my opinion...finally dont let it get you down as it really is nothing out of the ordinary so you shouldn't really worry about it anyway you don't need to be self concious about it.