If it's on your record then it might affect your chances, however usually they don't bother as long as you pay right away, and there would have been nothing anywhere that could link you back to it again. In comparison to other things, it is a very minor offence anyway, and there are some police departments that would be willing to overlook things like that as long as you have enough else to offer to them. It's definitely worth trying your best to get into the force, though. There's nothing you can do to change your past, but you can do your best to live an honest and hardworking life from now on.