This is good. Really entertaining. You say you never thought much about being a writer until recently. Some people shouldn't think; it's not their strong suit. In your case, I'm glad you thought about changing direction and giving the written word a chance.

You manage an interesting trick: at first glance one might think this is really a screenplay, or a radio drama, containing as it does dialogue and nothing else, but that would be a mistake. In truth, it's a lousy screenplay, and it doesn't work as a radio play either. In fact, I can't see it working in any medium other than the one in which it exists now—words on paper. The effects are all the product of writing, not speaking, not acting, even to the use of ellipses to suggest silent activity, something that works effortlessly here, but which would require at least stage direction in a script and sound effects on radio.

You need to edit a bit. Towards the middle, before her ex-boyfriend comes into the conversation, they start to repeat themselves. Keep in mind that the last thing you want is to recreate real-world dialogue. Conversation in the real world is a crushing bore. You want instead to create what sounds like it could be a real conversation, but the way it would sound with both parties focused on a goal. You've already shown how much you can get away with leaving out. Don't lose your focus when you most need it. They don't have to rehash the friends vs. relationship issues more than once, regardless of how much time a neurotic boy might need to deal with it in real life. Move things along. Your readers will reward you by remaining your readers.

I have no idea, simply from reading this, if you can write description, exposition, or if you can even come out of a simple declarative sentence with your tenses, and balance, intact. However, I'd be will to bet that you can. In any event, if this style is any indication, you might not need to.