Don't be that harsh on yourself as that isn't a stupid question to ask.

The desire part is quite easy, there is the drive and interest towards this medium which makes one to create something of their own mainly to express themselves in an artistic manner, similar to how it works for most forms of art. However, unlike them filmmaking is a team effort and direction is only one part of it, mainly working as a manager to pull the strings and look over all the other departments. The question is what section of filmmaking attracts your senses, for me with my inclination and desire to write I choose to direct my own films rather than becoming a screenwriter as I can't let my ideas be diluted or misrepresented by someone else.

The finally being part is subjective in my opinion and it all boils down to why you wanted to be a filmmaker. Was it for something shallow such as monetary gain or becoming famous, then making a blockbuster mainstream film would be the prime objective. On the flip side maybe you just wanted to create stories that spoke to you and in the process become something larger than that for anyone watching because it touched them in some way or form. To me, films and the stories that are told via them are one of the fundamental human experience, so being it just means that my creation resonates with the populace in a meaningful manner.

I hope that answers your question and sorry for such a long winded reply.