Anya,
You should write whatever you feel like writing. There are no rules if you're not doing this professionally yet. No musician is born into a musical pidgeon hole. Once they enter into doing music professionally, pidgeon-holing becomes commonplace. But before I go there, know that there are various music fields where having the ability to write in a variety of styles is important, including jingles, film scoring, industrials, and session work.
If you were to establish yourself as an artist, obviously you wouldn't put yourself out there if you didn't feel comfortable with your style, presentation, etc. You can forge ahead and do whatever you want and over time you will learn what various audiences react favorably to. Still, it's always best to write for yourself and not for the audience.
Keep in mind though that people tend to like some kind of consistency when they listen to a CD. So if you put out, say, an EP with a techno/trance track, a highly emotional acoustic guitar singer/songwriter ballad, a jazz tune, a new age piano thing, and a country tune, your audience may get a little confused as to "who you are". But no need to worry about this kind of thing now. Sounds like you're just getting started, so do what you like. Again, no rules.
If you want to pursue a career as an artist (and you're good enough) and you approach a label to get a recording deal, know in advance that they're going to want to see some kind of consistency, and this is where the pidgeon-holing comes in. The commercial music perspective isn't all that flexible when it comes to extremes of variety. Look what happened to John Mellencamp and Snoop Dog when they did nothing but change their names! The audience lost something consistent in their experience of those artists...
So for now, do your thing, learn, experiment, hone your craft, whatever that ends up being.
-=iS=-