Yeah, the only way to create an Apple ID for someone under the age of 13 is to make sure you use a birth year that makes them 13 or older on the FIRST TRY. Once you have a birthday associated with an email address Apple locks them in. That email address wont' be able to get an iTunes account until it's 13th Birthday.
There is a way to create an account without associating any credit card, but you'd need an iTunes Gift card or a prepaid credit card. That's what I gave my 13 year old niece and I load up 10-50 dollars every once in a while.
The thing is, If you have a kid who's under 13, it's probably better that they don't have access to your iTunes account because they can purchase things with your attached credit card not knowing that they are racking up real money in charges. If you do let your child use your ID, make sure it's password protected and that you don't give them the password EVER. Especially now with all of the "in app purchases" it's really easy to rack up a HUGE bill buying virtual smurfberries or whatever.
http://moneyland.time.com/2011/02/08/1400-for-smurfberries-why-you-should-think- twice-before-handing-an-iphone-over-to-an-8-year-old/
PASSWORDS wont' be hacked by children if they are never told what the password is in the firstplace.
Also remember that the iTunes TOS states that kids under 13 can't have their own Apple ID. So if you are caught they can delete the account...maybe more, not really sure. This is why they "lock" birthdays to email addresses, so you can't realize that you've made a mistake and go back and make the kid's birthday 10 years later and just keep going.