I've been doing art since I could hold a crayon, but I took a large break from drawing throughout grade school up until the end of middle school. Pur teacher gave us a sketchbook assignment for the year, but never actually taught us how to sketch, so I asked my mom how to draw stuff (because she's artistic and used to sketch/paint. Now her artistry is in photography). She then convinced me to take art while in high school, knowing I'd enjoy it, and I enjoyed it so much that my the end of high school I was skipping math classes (my strongest subject) to work on paintings and sculptures. I took to digital art around grade 11, using my tablet that I previously had for 2D animation, and then once I entered university for software engineering I kind of turned my back on art again. The school wouldn't let me take fine arts as a minor, and I didn't have time for a double major, so it wasn't until last year's winter that I decided to put more time into the hobby I love.
As for why I do it...? I enjoy the end results incredibly. Depending on how I approach the art, the process can be fun too (or meditative), but mostly it's for seeing the final works. This may sound odd, especially as an artist, but I lack the ability to visualize. I remember sensations and, well, "thoughts" as a sort of entity. I can describe a table, I know what a table looks and feels like, but I can't actually visualize a table. So art is sort of my artificial visualization. I can create the thoughts abd thus see them. My goal in improving art is to be able to better see my own ideas.
I like to tell people it's a useful skill, or that it has application in trying to convey ideas as a designer for software or, as I used to have deep interest in, games, but really I just want to be able to see my thoughts like everyone else does.