Most kids in the 80's we're being potty trained when they turned 18 months old.
I'm not sure if they were actually potty trained at that age or if they were just beginning to potty train.
In my opinion you could introduce the child to the potty at 18 months but I think it will take until the child is 2 or 2 and a half years old before they actually finish being potty trained to where they'll go to the toilet on their own when recognizing the need to use the toilet.