It's not "normal" or ABnormal, it's just the way some people are. Often, shy people don't have a much self-confidence and/or have low self-esteem, but not always. Some shy people simply prefer not to draw a lot of attention to themselves.
If you're shy & don't want to be, try focusing on all the things you're good at, things you know a lot about, then talk to others with similar interests. The more you do it, the easier it'll get! Being shy is something you can definitely overcome... IF you choose to! :)
it is common to be shy. don't get it mixed up with social anxiety disorder, that is something that is much more significant. regular shyness is nothing to be ashamed of or worried over. I myself think that shyness comes from the social role that humans have in our own social hierarchy. your level of shyness or social interaction depends on how dominant or submissive a person that you are in the social hierarchy