Last week, Knicks rookie RJ Barrett went to pick up a package for his grandmother. He didn’t even get out of the car, but someone recognized him from afar. And it blew his mind. “I really forgot that I play in the NBA,” he tells The Post. “It’s such a different reality that we’re in right now.” The 19-year-old is riding out the coronavirus lockdown with his family in Orlando, Fla., playing video games, chilling with his French bulldogs, Kobe and Kingston, and bonding with his little brother, Nathan.