My 33 year old daughter has been smoking since she was 17 years old - even though the rest of us don't smoke. She said it was peer pressure mainly and now she enjoys it!. She did give up for about a month last year and seemed to be doing very well so you can imagine how fed up I was when she started again. She did say she will give up - eventually.
It does appear that more young girls take up smoking then boys. I think like all young people they don't think it'll 'happen' to them. They will never get old and ill - it's just something they don't think about.
A young woman I work with is in the midst of having a very large tattoo across her back. Even though several of us have said that it will look horrible with a wedding dress on and even worse when she is over 50, where it will look like a large inkblot. Same attitude - it won't happen to her.