When to start stage 2 foods?

My son is almost 7 months old but he's roughly 4 months old, adjusted age. He's almost sitting on his own and starting to show signs of teething. Could I start stage 2? Or should i wait. His Dr said it's up to me. He's doing really good with supported sitter, opening his mouth when he sees the spoon and he watches me and gets excited when he sees the container like he does with a bottle.