Is it normal for my 19 year old sister to watch cartoons and never go out with friends?

I have a sister who is 19.. but she is not like any other normal 19 year old.. she dresses like a dag (has no idea about style), all she does is read books (vampire and fantasy books) and if she isnt reading books she is sitting on her laptop watching japanese cartoons with her earphones in. Is this normal?? im not bagging her out.. i am just worried about her because she doesnt seem to have any friends, and im worried that she is going to live a very unhappy life. I know she is doing what she wants to do but she has no clue about the outside world, she doesnt socialise, she has never had a drink or gone out with a friend for a drink... is there a way that i could encourage her to act her age?? i mean she basically vomits at the sight of 'normal' clothes, she hates the thought of leaving the house on a weekend and thinks that anyone wearing 'nice' decent clothes are just sluts... "in her words"... is this normal?? i just want her to have some fun while she is young and go out and experience what normal 19 year olds experience before she turns 40 and thinks to herself 'what did i do when i was a teenager?'.. please help!