OK, so you raise your risk of identity theft as per above (lying about the date is the best approach). Except that it is a violation of the license agreement section 7.1 to do so (“account info will always be complete and accurate”). Hence Adobe can keep your money and terminate your service if you lie about your date of birth (see section 6.5c on non-refundable fees).
What risk? Here’s an example: news recently emerged that a vulnerability in Adobe’s ColdFusion software led to a hack that may have exposed 160,000 Social Security numbers and 1 million drivers license numbers.