My pediatrician said that the only foods to avoid giving a 12-month old are:
eggs - they recommend waiting until 2 years of age
peanut butter and any nut product - wait until 3 years of age
As long as your son didn't seem to have an allergic reaction to strawberries, he should be fine. :-)
If I am worried at all about how my son would react to foods, I just give him a little taste first and then wait to see what happens. Although...he is such a picky eater right now, all new foods that I try to give him are rejected and often times thrown on the floor (sigh!) LOL
Good luck!