My character Aquamarine is from HomeWorld originally much like Pearl and Garnet to be kind of a guide to the ones that choose to be as you said "new" and not knowing much of anything. Some of these new Crystal Gems decided to stay in there holes or hide. Born earlier but choosing to avoid the war so they would have probably learned some things on there own.
HomeWorld and Peridot are trying new things in the Kindergarten which would be of concern to them. They won't have much ties if any to Steven and the other till much later unless someone wishes to play Canon character, then they may be introduced earlier.