D.G.
When you give it to them, LOL. Most babies love it. I read this online to get you a more professional answer:
Introduce juice when your baby can drink from a cup. Don't serve juice in a bottle. Your baby may keep the bottle in her mouth too long, which can promote tooth decay. Give your baby no more than 2 ounces of juice a day. You want to make sure she has room to take enough breast milk or formula.