*Bureau of Labor Statistics, U.S. Department of Labor, Occupational Outlook Handbook, Music Directors and Composers, on the Internet at https://www.bls.gov/ooh/entertainment-and-sports/music-directors-and-composers.htm (visited March 24, 2022).
A bachelor's degree requires the completion of 120 credits so it depends on whether you already have your associate degree and how many credit hours you take each semester. The average time for an online degree is two years with an Associate's if all your credits are accepted and three to five years without an Associate's. However, if you decide to take your courses as a part-time student (12 hours or less per semester), it can take 6-8 years to graduate. So be sure to talk to you guidance counselor about what classes you should take and when so that you can avoid extra semesters and the price tag that goes with them.
Besides your core classes and instrument of choice you'll need to take courses on Music Theory, Composition, Conducting, Music History, Music Literature, and classes according to your degree or minor such as Education or Business courses.
A Music in Theory degree in Liberal Arts is great if you want to perform but not if you plan to teach. Likewise, if your goal is to work on the technological or business end of the music industry, you need to verify the corresponding courses are available before you enroll. Just because an institution has a music program does not mean that they have the classes you will need for any/every career in the Music in Theory industry.
Look at the school's student statistic or student numbers page to see the graduation percentages. If you can't easily find the rate of graduation it may be a red flag, because most schools brag about their rates. You can also do an online search or contact the admissions office to verify the graduation periods and rates. If a significantly low ratio of students are graduating, or graduating on time, it may indicate that there are issues within the school itself or your program of choice that will make it difficult for you to graduate in a timely manner as well.
Your degree won't do you much good if you can't find employment after graduation, so pay special attention to the job placement assistance your school of choice offers. Look beyond the post-graduation employment rates posted on the recruitment page and dig a bit deeper to find personal opinions of other students on forums and social media pages.
See if the school offers internships and job fairs for final semester students. Look for interaction with major employers in your field of choice to get a good feel of your chances of employment after graduation. Often major employers cultivate partnerships with colleges so that they can interact with students throughout their education and streamline their employment recruiting process.