I think I understand your point of view, but I would argue that even an aesthetic category such as 'poetry' can exist without sentient beings to experience it. Ultimately the category is not defined by the things in it, but by the criteria that define what is in it, and so the category of 'poetry' is populated by everything that fits a definition along the lines of: combinations of words or arrangements of things that would spark an aesthetic experience, rather than things that do spark such an experience. This is necessary if we wish to include works that have been created, and which presumably do not generate precisely those feelings in the author, but which have not yet been experienced by others yet. I would suggest we should include such works from creation, rather than them suddenly becoming poetry when first experienced by an audience. If we use the latter definition, who creates the poety, the author or the first audience?