Though he did commercials among other things, Ridley Scott was 40 when he made his first feature.

I know someone from my hometown who pinched every penny he made starting in his mid-20s, spent the last 10 years waiting for prosumer equipment to advance to a certain point (while learning all he can about how the technology works), taught himself the basics photography and editing, and learned the the ins and out of film theory and history (while watching a couple thousand movies), as he consciously honed his skills as a writer with a dozen of not-meant-to-be-produced scripts. He is now 36 and starting his first feature.

A lot of professional filmmakers suggest to just get out there and make a movie, which is pretty solid advice, but I have a lot of respect for the above mentioned guy. Sometimes you just got to find what's right for you.