For me at least, the present was so chaotic that I had no choice but to deal with that first. I suspect that is true for many people. Once I stopped a lot of the behaviors that needed to be stopped, once I had a little serenity in my life then...and only then did I have the time or the energy to look back. The past will always be there and by working on the "now" my knees locked up a little less whne I started looking back.
I couldn't even read ACOA literature without looking at my own flaws as a parent...there is no way I was ready.
JT