How to start on being a Marketing Professional when actually you have not earned a degree for such & never worked in Marketing Industry?

Dear Lani, this is how I see it; start marketing, and in your way you will learn how to be a professional. And of course, this wont be enough; so after you start, make research, ask professionals, look around you for example, learn how to judge them, have a good look on any kind of advertisement; TV, newspaper or internet, a picture, text or even a video. In the end you will become a professional; if you worked hard with these.

You should seek to take some courses whether it be to audit courses or find some programs online that offer free courses in the subject matter.
If you could find a place that offers a certificate program as these programs are often shorter in length.
You need to invest in knowledge acquisition of the field knowledge.
I am currently refreshing my knowledge in economics through Khan Academy.
It is a free online program that offers free courses in some areas.
I am not sure if Marketing is one of those courses but it does not hurt to check it out.
Additionally, If you could volunteer your time with some organizations or ask to shadow a marketing professional that could help build your experience.
You will have to start from the beginning and build a foundation.