As far as investigations is concerned, I suggest you think about what skills makes a great investigator -- some examples may include curiosity, analytical skills, love of research, problem-solving, powers of observation, but think up your own list, too! -- and try to develop these skills in your own life. Especially the research part, which you can start right now: you can investigate being an investigator!
Consider in what context being an investigator interests you. If it is law enforcement then research further education opportunities in criminal justice, criminology, forensic science, etc. If it's tax investigation then research further education opportunities in business, finance, forensic accounting, etc. If it's Investigative journalism look into journalism and English degrees. Use your current investigative skills to figure this out :) Identify what credentials you'll need to be the type of investigator that interests you most!
Next figure out how to get those credentials - is there a college, university or academy that offers the training? If so, what do you need to get admitted. Are there prerequisite courses? What is tuition and are there scholarships?? For instance, to get into the famous U.S. FBI academy at Quantico (seen in so many western movies and TV shows!), you need at least a bachelor's degree (e.g., 4-year undergraduate university degree) and 2 years relevant work experience, among other basic requirements for applicants. I share this only by way of example, but you should research what is needed to follow the path you are charting for yourself. Once you see the road to becoming an investigator, the you can align yourself to it.
Lastly, consider reading biography/true stories (non fiction) about investigators from different types of practice to get some sense of what each involves. There are lots of books out there write about different types of "true crime" and political investigations. Of course, the books will focus only on the exciting parts -- no one wants to publish a boring book! -- but it might give you some idea of the what the profession offers.
Desiree recommends the following next steps: