It's only 'normal' if it meets your definition of 'normal,' which is subjective. I don't believe masturbation is normal or healthy, or morally right. It feels dirty to people because it is! Trust your feeling because they're often right and people use intellect to override wrongly often.
Its personal prefrence really. I think its ok becuase like said above its better than getting STD's and also most of my friends do it but if people don't want to i think you should respect their choice
because you're wasting energy and focusing on a solitary activity that isn't productive, on the other hand you could find a boyfriend or girlfriend and focus your sexuality towards them, which would be co-operative and helpful, instead of introspective like masturbation. Morally I think it's wrong because sex is meant to be had between two people who are sexually mature, not a person and a vibrator or their hands. I think if you feel bad about doing it it's right to listen to your heart and not do it.