If you have guns, you must know how to use them properly or you can end up in an unsafe situation, or if you don't use them at all they just become museum pieces.
I've never had formal training. My dad "taught" me to shoot, but as I grew older and more knowledgeable, I realized that he wasn't very good at teaching anything. He lacked patience, and frankly, empathy.
As a consequence, I have found it necessary to educate myself on firearms and their proper handling and use. I think I'm also going to take a concealed carry class so I have some formal training. This also allows obtaining a permit from the state, which would allow me to transport and carry guns in several other states that have "reciprocation" agreements without having to worry about the local police hassling me.
One of the main issues I have is that I get nervous when I go shooting. This is because I don't go shooting often enough. You don't want to become cavalier with a firearm but you should feel comfortable. I'm working on it.