I used to dream of martial arts, and oddly enough of drawing...however, over the last few years I seem to be too tired to remember anything except waking up...being tired.
In any case, I think it's nice. To me it means you are enamoured of what you are doing and considering things in your subconscience. This is not bad...this is something to remember and be happy about.
To enjoy something enough to dream about it means that there is happiness there that swells beyond your day time considerations.
And like someone who just gets into a hobby and who has youthful enthusiasm (regardless of age), it makes me smile!