Here's what I did when was in my late teens & early 20s, and taught myself.
1. Copy famous artworks that you admire -- even just drawing in a notebook is great, to start.
2. Once you can copy art that you really like, start adding your own flair to things, develop a personal style
3. Experiment more & more
Just like with programming -- there are a ton of great books about how to paint, how to mix colors, etc.
You can buy books and work through them, whatever is most fun.
There are 2 key points, though:
* The only way to get better is by painting... you'll have to paint a lot
* You'll want to paint a lot +only+ if you're having fun.
So don't worry too much. Just grab some paints and enjoy yourself. It's a great hobby.And try everything you can -- watercolor, oil, gouache, ink brush, encaustic, using the palette knife only, mixing with collage, pastels, all will teach you something. Just be consistent, and you will get good.