For my first serious attempt, should I buy a blank garment online and sew a print onto it?

I’m going to attempt my first serious homemade costume for concerts and festivals. I will be making a hooded cloak with a druid vibe, and so I want to find a cool nature print for the back of the cloak, along with another material that I intend to stitch onto the inside of it. Once that is done I think I will be able to attach other accessories and trinkets to flesh it out and give it character.

I have absolutely no experience whatsoever in creating a garment from scratch, and I feel like it would be easiest if I were to just buy like a blank cloak on Amazon that is a neutral color, and then just look for two other fabrics for the interior and exterior that I can sew on. Is this a mistake, or is this a viable path forward? The primary reason I want to do this is because I am not confident that I will be able to properly measure out the material needed to make it completely from scratch (dimensions etc.).

I am confident enough in my ability to attach a new fabric to an existing cloak, but not much more than that lol

If this is an OK plan, what material should I use for the base cloak / what materials should I stay away from?