App Inventor Vs. Java?

I just started learning programming about a month ago. I was inspired when I got a brilliant idea for an app. I'm learning Java and loving every step of it. However, I want to get my app out there ASAP. Is MIT's app inventor legit? Should I design my app that way? Are there royalties I have to pay if I use the app inventor? What I'm asking is- should I use app inventor or should I hunker down even harder and get better at Java?

If you need to get the app out there ASAP app inventor would probably be the fastest way. I don't think you have to pay any royalties for apps made with it. I would use it for my first app if I need to do it fast, but continue learning java and android to make more complex apps later on.