Don't change your major. Criminal Justice will not really help you much in getting a LE job. Finish what you're doing, meanwhile contact your local departments you are interested in working at and find out what specific requirements they have. Some departments will hire you, then put you through the academy, others you have to put yourself through first. What state are you in? Most departments are more concerned about your background, criminal involvements, and honesty than they are about your major.
"The inherent vice of capitalism is the uneven division of blessings, while the inherent virtue of socialism is the equal division of misery." - Sir Winston Churchill