I know this is an old post, but I couldn't help but comment.
I've been self-taught for a long time. Like, this year is the first time I even took a professional college-level art class (and not even at an art school, mind you). A lot of what I know now is what I learned on my own and getting advice from people who were professionals and posted on online or self-taught artists who were experienced and posted advice. A lot of it was also from trial and error.
However, I will say this -- taking art in college has helped push my abilities farther and helped me realize how much knowledge I had already had. Like, even if I was pretty good before that, with the class, I was even better. The instructor pushed me to explore out of my comfort zone and dive into new mediums. While exploring those mediums, I physically saw how a lot of my self-taught experiences made my art work pop out. With my traditional work, I was amazing with charcoal, despite rarely using it beforehand. And the exercises in the class helped me better my skills with perspective and realism in the human form.
This is before I took that art class:
This is what my art looks like after it:
Example 1
Example 2
Example 3
For me, I say it doesn't hurt to take an art class if you can! Being self-taught doesn't necessarily mean you learned it all on your own, after all. You just happened to learn outside of the classroom setting. But that doesn't mean you can't take a class and get a new perspective on things. Of course, that also doesn't mean you HAVE to go to an art school or shell out a ton of money to do so.
If you can, see if there are sessions around your area that are free or at least inexpensive! Find a program that can give you a new pair of eyes towards art. But also don't be afraid to explore and try things on your own