Initially, when you come across someone you like, infatuation sits in. Lust not love, may take over...we can get so caught up in the moment of finding someone who's appealing and attractive at initial conversation that we may get overly anxious to make sure they don't get away.
However, it takes years to truly get to know an individual, if you decide to become exclusive rather quickly, there may be some characteristics that pop out of the woodwork a month or two down the road. If you were to casually date then maybe those traits would arise in that second month and you can be better equipped, less infatuated and more logical on how to communicate an issue at hand.
If you have had emotional trauma in the past with relationships, it could be causing you to want to rush. Maybe you don't want to be alone, you're dependent due to the crap you have been through or just want someone by your side however, you have to make you happy first. Before jumping into the arms of the guy/girl you think is your dream mate, analyze why it is you feel you need to rush.