Peanut allergy?

I gave my son the waffles fries form chik-fil-a. I didn't realize that they are fired in peanut oil until later. He didn't have any kind of reaction or anything. Does this mean it is ok to start giving him peanut er and things of that nature? His ped dr told me to wait until he was between 1 1/2 and 2 yrs old. Should I wait until I talk to his peds? Hes about 16 months old now.