Adobe does offer a free trail for 30 days. Additionally you can get free software alternatives. These programs work similarly, but are not widely used professionally. I’d suggest getting them to “mess around” and practicing general concepts within design before you invest in Adobe’s products.
I’d also urge you to read up on design as much as possible. Graphic design is not a licensed profession. With enough hours put it, you could do it freelance. This is the long way to build a career, but it is possible with a lot of effort.
My no-cost (except time) recommendation is to take one of these free online graphic design courses, using either the Adobe software trials or free software and read a few books on the topic of design before you consider a career change.
I find that many people enter graphic design thinking it is the same as being a graphic artists. I’d also suggest you read this article, “Graphic Artists vs. Graphic Designer,” for a basic understanding of the difference.