It's quite worrying if you're not 13 and are masturbating. I hope you're not doing it because you feel you have to, out of social pressure to do it. In a few years you will know why people do it and how good it feels, don't rush into it if you don't want to.
To answer your questions.
1: It is normal and perfectly healthy.
2: An orgasm is a point of total climax where your body shakes and you feel a total release - you also secrete fluid.
3: You don't feel anything because you're too young to get the sensation from the clitoris. Try again in a few years if you really want to.