I'm still a noob, but I wanted to build something for work. As a Cardiac Nurse with no techy background I found HTML, CSS, JS, and jQuery were easy to pick up (especially with the help of Code Academy and other online resources). My final product 6 minute walk test app is here: http://sixmwt.com. It's for clinicians like myself to use in a Cardio-Pulmonary setting.
I am also in a similar situation and I say go for it. I'm a Coronary Care Nurse (8 years and counting). I was previously employed as a Cardiac Rehab Nurse as well and it was very frustrating as I did not have creative freedom to manage problems I wanted to solve in that industry. Like jnardiello I'm in my late 20's, no kids, no mortgage, just newly wedded and have a very supportive wife. I basically wanted to solve a specific problem at work and I came across Web Apps. This changed my world and I decided to build one for a specific purpose at work (sixmwt.com,6MWT App). I did this in my spare time and decided only two weeks before my wedding (last month) to quit my Cardiac Rehab job and pursue web apps. I still work as a Cardiac Nurse once a week with the flexibility of picking up extra shifts when I do need to. It's scary as hell as I am a clinical person and have no experience with the IT industry. I basically stackoverlow, youtube and google things I need help with. I am very lucky to have a friend who is mentoring me in .Net/C# at the moment, I won't bore HN with that (you can read more at neilbo21.wordpress.com). I've been working on my resume and portfolio and I guess that's the main thing to work on. Show people what you can do (especially on GitHub). This advice has been recently reinforced from a great Software company (@Net_Engine) who I met with the other day to help guide me through this life changing decision. So I guess if it is any source of inspiration...ask yourself why you want the change, what is it about programming that you love? I guess I'm still in the honeymoon phase of learning something new, I love the instant gratification of writing a few lines of markup code and solving problems with web programming. I'd love to delve deeper and make a real CRUD app and use databases etc.
I wish you well in whatever you choose to do, Good Luck.