I prefer informative, but then it IS very difficult for me to get into heartfelt pieces when I don't know the person writing, because it's just hard to care about an anonymous avatar. The exception for me (and seems to be for at least some other people) are the heartfelt pieces that readers can really relate to, especially on topics that are difficult to put into words. I personally have two heartfelt pieces, one on the death of my 3 1/2-year-old nephew and one on cutting, that have gotten excellent responses. I'll admit they are not the best examples of my writing because I had to fight my way through a lot of emotion to get them out, but people who have experienced similar emotions seem to appreciate the effort, and appreciate someone who is willing to openly talk with them about this subject.
For you, trust me, there is still PLENTY you can write about. I started writing professionally at 16, beginning with reviews. I wrote reviews on a lot of books, movies, and CDs that others didn't, because most of the others were older and weren't interested in the same things. However, the market for them was huge because other people my age wanted those recommendations. Then I got into writing articles aimed at mothers who were having issues with their teenaged daughters, and a lot of people really seemed to appreciate and benefit from hearing the perspective of a teenager on the subject.
My advice -- sit down with a piece of paper and start listing off your interests, things you like to talk about with your friends, places you like to go, and just keep writing until you run out of ideas. Grab one thing off the list, and write about it. I warn you, this is an extremely addictive process.