Yes – You Are! There aren’t any rules for art journaling.
It’s not a special thing that you have to do “just right” for it to count. Your art journal doesn’t have to be perfect or perfectly orderly. It can be a diary with only text or it can have only images or be a combination of both. It doesn’t have to be completely original on every page – it’s OK to use images from other sources. There isn’t anything special about the tools or materials – there is no “correct” pen, ink, paint or glue. It’s not any particular shape or size nor does it have to have special paper for the pages; it may not even be a book at all.
The most important thing about YOUR art journal is that it’s yours and it pleases YOU. If there was a rule, that would be it.