Can't say that I'd recommend my method: jump in with both feet, and learn as you go.
I signed up for my license without any race experience. At the time I didn't know you could race as a citizen. Now I know that I should have tried citizen racing first. I really think there should be some sort of a test (like you have to take to get your driver's license) to get a racing license.
The biggest thing I've learned so far is, boy, those Cat 4 racers are FAST! I really just own a basic, entry-level bike (Giant OCR1). I have recently upgraded to lighter weight wheels.
I think if you've been club riding, you're a step ahead of where I was when I jumped in. I think that's one of the essential skills of racing: knowing how to ride in a pack.
Good luck with your decision! Racing is exciting and fun--and it makes you feel really good when you finish.
If you can read this, take a pull.