It depends on the career path you would like to choose. Every job requires its own training and the timeline varies from one to another. Also if you already have some knowledge on the subject or you possess the required skill level then you may not require long training. So the advise would be to first find out what are your areas of interest then search for available training options. Hope this answers your query.
All the best for your future.
As far as training goes in any interests in your life, it should be a daily factor. Everyday you should be training your mind, soul, strength and body. Set up specific reps and scheduling dealing with the outcome you are looking for concerning your physical health. After that set up time and find quiet locations in order to bookmark PDFs, read books and research online topics dealing with Criminal Law and Justice coupled with Sociology and Psychology. Last but not least meditate, study and become the art as well as the profession you are seeking.
I wish you the best on your journey.