[JeremyNT]

I switched to software development from a related IT field (ops) when I was a little older than you are now.

In my case I had existing knowledge of the basics and had programming experience (but not as my primary job role, nor in a team).

Here is what I can suggest: if you can at all leverage your existing domain experience it will serve you well. Try to figure out whether your employer can place you in a role where you can contribute in some way using your existing skill set while you further your software development skills.

Having taken some computer science classes, read programming books, and having programmed off and on in small things for many years was helpful to me, but I can't overstate how much that was all eclipsed by raw experience doing the job day in, day out. I quickly realized that there is simply no replacement for hands on programming experience, and having a team around to help fill my knowledge gaps was invaluable.