I agree with Aval - get the story down first. The first draft's purpose is to get something to work with - something you can hold in your hands and look at and start to craft.

I'm writing a story right now where I've switched tenses, POVs, and even if it's 1st or 3rd person. Not all my characters have names yet. There is still a lot left to be desired with the technology in the story. However, that doesn't matter, because the important thing is to get the story down. I'm going to pick a style that will fit the story later when I have the whole thing to look at and get a better idea of what my story needs.

So, don't worry right now *how* you're writing it - just write it! No one ever said you have to show people your first draft.