Hey Michelle,
Certainly for the time being I would hold on to the cards. Once they are destroyed there's no going back.
I just started telling my 4 year old daughter a couple of basic things about her surgery as she see's her surgeon every 12 months.
All I can go on is how my family treated my adoption. I knew from about 3/4 years of age and can't remember being told, I've just always known. Obviously the very first time I was told wasn't too traumatic as I have no memory.
My parents had a fantastic story about all the problems that happened when they got the phone call and how they had to run out to the shops to buy baby things etc before they could pick me up. I thought it was a great story and apparently they had to stop me telling other children that they weren't as special as me because I was picked out.
Getting to the point - I think kids like to feel special and love a story that's just for them. I think it's good to tell them young how some things didn't go to plan and that alot of people had to look after them when they were a baby. It turns a negative into a positive and they grow up always knowing but feeling comfortable with the drama's around their birth etc.
That being said, I'm sure a Psycologist would have some very good suggestions.
