Is it OK to vaccinate a 10 month old for chicken pox?

I am 37 and have been diagnosed with shingles. My 10 month old son has not been vaccinated for chicken pox yet. My pediatrician said to bring him in and if he wasn't showing any signs of having contracted chicken pox yet, they would give him the vaccine for it. She said that normally they would not do it until 15 months. So that got me worried. I looked it up and the vaccine appears to be approved for kids aged 12 months to 12 years. So my question is, is it OK to vaccinate at 10 months?