I would just like to reword your question to reflect my view of any profession. So, I would ask:
How do I begin the long journey of getting certified/educated to be a fitness professional?
Anyone that feels getting a certification is the end of the process is just looking for a job, not a profession. Jobs are usually boring. Professions are for a lifetime.
Get a degree or certification. Then learn and learn and learn some more. Look for areas of study in the world of fitness that interest you and become as knowledgeable as you can. Practice what you learn. Seek assistance in applying what you learn when you are unsure. Don’t be to proud to ask for help or to ask questions.