Yes, it will be to your advantage to get a Bachelors degree in Criminal Justice as opposed to not doing so.
I knew someone who did get his B.S. in Criminal Justice and was accepted into the police force as a police officer. After a while, there were some administrative openings which required a B.S. He applied and received the position. He wouldn't have had the opportunity to advance in that manner if he didn't have his Bachelors Degree. So, yes, I say go for it. There will be a variety of courses you'll take that will advance your understanding of the work you will one day do. You will also have experience with written and oral skills, developing them through various college courses. That will greatly benefit you as a police officer. Best wishes to you in your education.