My oldest daughter had a severe allergies to milk, egg, & wheat so her ped suggested we give her peanut butter to get some protein. I think we started giving her PB at 1 or 1 1/2.
Soy butter is a good alternative. I give soy butter to my 2 yr. old because peanuts are banned at daycare.
You can ask your pediatrician if you are concerned.
Here is an article:
When Can I Give My Child Peanut Butter?