it is natural for you to get excited. when excited masturbate. there is nothing wrong with it. over a period of time, get a partner and enjoy while it lasts...
See the above videos. They will open after few clicks. Click till you get them open. they are good for education purpose.There are good posting on this part of website. Read them. You will get insight in the sexual problems.
It is normal for young one to think and get excited by seeing or thinking of genital parts of member of the opposite sex. In such situation, do not get perturbed, let the thought come and go. Do not concentrate on thought and do not get perturbed. when you don't concentrate on thought it will do away.. You may also try to concentrate on breathing. when breathing is normalized, you will feel calm and quite.slow and deep abdominal breathing calms your all emotions. Google, abdominal breathing, learn it, practice it ever day and do it when you feel aroused by sexual thinking.
Sometimes you may masturbate. It is normal. Do not masturbate with dry hands. Lubricate your hand.Do not stop breathing. Keep your perineum relaxed.Do not do it in prone position.Keep your bladder empty. You are not doing any crime when you think about opposite sex or when you masturbate. Take it very lightly. Take care of your health by doing exercise, eating good food, keeping company with good friends and concentrating on your career.
Wish you best of luck.