If i was exposed to a large amount of carbon monoxide as a child, could it affect me as an adult?

Probably not: Co poisoning is caused by formation of carboxyhemoglobin on red cells. That prevents red cells from picking up oxygen. Since you did not succumb to co poisoning, you have got rid of the abnormal hb and there should he no after effect.

No: This agent is a transient toxic event that never stores up in your system.You essentially remove it over time.There is cance exposure to this off and on through life but these minor exposures don't have any significant effect because your body is designed to remove it.