Sounds like you're talking about small talk, right?
Perfectly normal for conversations to start with it... it's pretty much the order of the day. Nothing wrong with trading a few bits of small talk, but you want to get off it as soon as possible.
So, she tells you about the test she just had or the crazy thing her roommate did... no problem. You don't always want to be in deep conversation, and in fact if you do it much outside of dating scenarios and/or you go deep and then don't take the girl to bed, you stand a very real chance of quickly ending up as her really cool friend she has lots of good conversations with.
My advice is, if you're not moving things forward with a girl, actually skip deep conversation altogether and just stick to small talk and banter, until you're ready to pull the trigger and advance the interaction.