Hi Darren,
What my understanding of 'first love' is, when you first come to an understanding of who Christ is... basically the Son of God that came in human form and died as a sin offering. Whenever you came to this understanding and for most that would have been in church, but maybe you came to see this in your own studies. But it was whenever you first came to know Christ as the Savior and found joy in that. So whatever age and where ever you may have been does not seem to matter so much, but that you did come to believe that Christ was the Son of God.
I was a young adult and even though I did not know the truth at that time I was very happy to understand that Christ was my Savior.
But after the joy of finding out about Christ at first we all lose this 'love' in one way or another. Either the church overshadow this with their own doctrines or we get lose in the cares of the world, but we do lose it. Then at the appointed time God draws us back to Him, it's only a few in this age, but eventually it will be all.
That how I see it, I hope that it helps.
mercy, peace and love
Kat
p.s. Jackie Lee, Herbert Armstrong was the founder of WorldWide Church of God, Ambassador College and the Plain Truth mag., Garner Ted was his son.