What are some good blog topics? Wordpress (.com/.org) or Blogger?

[CurlyQs]

I'm a 16 year old girl looking for a purpose or area to base a blog around. I love beauty and fashion, but I also find analyzing issues or new things in my community/society interesting to write about. I would like to pick one topic to have my blog based on as opposed to a mash-pot of topics on one site. What purpose can my blog serve? As a blogger, is it better to post once a week on a topic (topics such as beauty) or whenever I find something to blog about (more in the case of issues in the community)? A list of possible topics to base a blog around would be great! Experience or guidance for a new blogger would be much appreciated! What do you think I should blog about to attract viewers? Last question: who wins? Blogger or Wordpress? I cannot wait to start blogging! Thanks a million!!!