There are many children of the Force (potentials) out there who were identified, but not brought into the Temple. A whole list of them was kept on file in the Temple's Archives. ANAKIN: "Who's Bolla Ropal?" MACE: "He is the keeper of the Kyber crystal, the data on which can only be read by Holocrons." AHOKSA: "What's on the crystal?" MACE: "A list of every known Force-sensitive child in the galaxy. The future Younglings. The future of the Jedi Order." Many of these Force sensitives will never make into the Jedi Order. Just as not all of the Dagoyan Masters of Bardotta are not in the Jedi Order. Just as the Nightsisters and Nightbrothers of Dathomir are not part of the Jedi Order. These people would grow up like Rey did, not knowing about the Force and living a normal life for years. In the old EU, the Jedi who didn't become a Padawan to a single Master by the time they reached their teens, were sent to work in the Agricultural Corps. Obi-wan was going to be sent there, since Qui-gon had initially refused to take him on. He wound up changing his mind after a couple of adventures during a trip together. In TCW, Ahsoka was allowed to leave the Order when she was fifteen, after she had been cleared of bombing the Temple and committing murder. That was true, but it was also about Luke fighting a Sith Lord when he wasn't ready to do so. Obi-wan saw that conflict coming and saw paths where Luke would fail or fall. I don't think the Jedi just kick someone out, if they haven't gotten a grip. They would, I assume, still be paired up with their Master or assigned someone else. When Ahsoka left, she was as I noted, fifteen. But she chose to search for Maul as he was the only link to finding out who Darth Sidious was. Most kids don't leave on their own, based on the way it's been described. That few Jedi have left the Order, so odds are they wouldn't want to go on their own accord. But say that there was someone who did want to leave, if the Jedi didn't do something like the Agriculture Corps, they would probably see to it that the child is placed somewhere positive for their own good. They probably wouldn't be sent back to their families.