1. Immigrant petition approval date: In your case, petition is I-140, approval date is July 14, 2007. What is the first date after I-140 approval is your PD turns current? July 14, 2007, current for all EB1, EB2 and EB3. So the date of this step is certain and has passed, so your CSPA age is frozen.
2. What is your CSPA age? 7-14-2007 minus I-140 processing days (about 30 days from June to July 14), so it was child's age at the time of filing I-140 in June, 2007. So even before filing I-485 on 7-6-07, his age was frozen in June of 2007.