H.H.
I gave mine a little juice at 4 months and only gave juice to them in their sippy cups not a bottle as the extra sugars in juice drank from a bottle can cause tooth decay. It also helps them learn to use the cup when they like the juice taste and that is the only way they can have it. I usually gave them 1 ounce at a time and they drank it when they were eating at the high chair or mixed it in their rice cereal. They didn't get juice everyday.
They didn't start eating any other foods until 6 months.