What kind of writer do I want to be?

As I'm working on Book 2, I'm faced with a question - what kind of writer do I want to be?  Book 1 (Secrets of a Summer Village) is a coming of age mainstream fiction/YA crossover.  It's fairly light-hearted, upbeat, and positive.  The feedback I've gotten is that it makes readers feel good and learn something at the same time.  It also makes you feel good when you're writing happy, positive stuff.  That said, I don't want to write fluff.

In book 2, something bad is actually going to happen to the main character.  I am pretty sure I know what this bad thing is, and it's really bad.  But I don't want to write a depressing book.  The first voice I gave this as-of-yet unnamed character was too depressing.  I didn't want to make myself depressed having to write her.  So then I found a much more upbeat, cheerful voice for her.  It was so fun to write, and it just flowed out of me.  But then this really bad thing is going to happen to her, so she won't be able to keep that up, and I don't even know how this voice would have to change after a tragedy.  So I have to find another voice.  Something between depressed and polyanna.

I also have to choose an age.  Is this going to be mainstream fiction? YA?  Crossover?  I'm leaning towards crossover.  What I hope I'm writing is intelligent YA that adults can enjoy, since in this modern world in which lines are incredibly blurred, young adults often read mainstream "adult" literature (I sure did when I was a teenager), and plenty of adults unabashedly enjoy YA.  I was thinking of making the main character 13, but then I was told that 13 is a black hole because it's considered too old for Middle Grade novels and too young for YA.  So my main character needs to be either 12 or younger... or 15 or older.  Which is a shame because I think that 13 is a fascinating age.

I think my main character will have just turned 15.  I'm not ready to write Middle Grade books yet, though I hope to one day.  What I mean by that is that I still remember being a teenager, but my memories of being 12 are much murkier.  I'm planning on waiting until my children are "middle grade" readers themselves before I can imagine that world again.

So, what kind of writer do I want to be?  Second book will help steer me in a direction.  First book was a wild card of sorts, but second book will make me lean towards a genre... or not.  Something that has to happen for me no matter what, is that I have to like the main character and enjoy writing the book.  Bad things may happen, but the characters cannot and must not be destroyed by them.  I want to be a writer who people enjoy reading.