I highly recommend that you do lots of listening of the music you want to create. If you wish to do movie scoring, for example, then learn how to read music and study scores of great classical composers as well as scores of John Williams and other film composers.
It's never too late! The craft of composing is a skill that you develop, it's not something that anyone is born with - even Mozart had many teachers and studied composition :)
I think that is very sound advice. I hadn't considered it, but I suppose that learning to read music would be necessary to study composition. :D I am really interested in composing for films and games (and also stock audio), but I have been focusing my attention on practice (of Cubase and EW software mostly) in the form of rewriting an old metal album I contributed to as epic symphonic metal. So I've been listening to lots of heavy metal in that spectrum (stuff like Mechina, Blind Guardian, Brymir, Dimmu Borgir).
It's very interesting what computers have afforded independent musicians, but there is so much to learn. Not just composition, but also production and performance. It is, without a single doubt, a lifelong pursuit. :)
You inspired me to go work on some stuff and I hate it/don't hate it! ? I guess? I dunno? Lol. I'll share it once it's more developed :)