Of course you will masturbate. Sex/masturbation is not a luxury but it`s a need. Especially in your age, that`s very normal. If you dont masturbate, it will effect your psychology, your mood and your daily life in a major way.
However, I think you should try not to masturbate while you are fasting. After your ifthar you can do whatever you want but try not to do it while you`re on fast. Dont worry, God will understand your age and your situation no matter what.