Bill, I don't think you're going to find your ancestor's date of birth in any Confederate records. I've transcribed literally thousands of Confederate service records, and I've never yet run across a single instance where a soldier's date of birth was recorded. In something over half the records I've transcribed, the soldier's age is recorded; and maybe a quarter or less listed the county and/or state of birth. Of course, I've primarily researched Arkansas and Louisiana soldiers and regiments, and perhaps other states kept more detailed records.

If your ancestor later served in the U.S. Volunteers, he or his widow may have applied for a U.S. veteran's pension. Those records tend to be much more detailed in terms of personal data than service records are, and is probably your best shot at trying to determine the date of birth.

BTW, I got your email and I'm trying to locate the source for that 6th Texas journal. I found it online somewhere, but I'm having trouble finding it again. I'll let you know if I can track it down.