Brian, I started out in IDPA (13 years ago) all excited about the latest OWB Kydex Holster and the ubiquitous Glock 34.  I had a ball making SharpShooter in SSP and ESP for about 8 or 9 years until I shot a "Carry Equipment" match and really enjoyed shooting with my Glock 19 and IWB Comp-Tac (that I carry).  Since you essentially can not go down in classification, I was stuck with the dilemma of being competetive with my G34 and OWB or using my G19 and IWB 'for fun'.  I stuck with the G19 and had fun (and built confidence) until CCP came along and allowed me to be competetive again (and still have fun)!

I have 2 suggestions for you:

1. Start out shooting your carry equipment - I have seen a lot of people learn a lot of things about their equipment and abilities by doing this.  It also gives you a chance to see and try the more competition oriented options.
2. If you then go the competition route (another fine choice), consider leaving yourself a division where you could still shoot your carry equipment more competitively if you choose.

Bottom line - whatever you do you will have a ton of fun, become a better shooter and be hooked on a fantastic sport like the rest of us - Welcome Aboard!