Stephen ­Webster, Anna Ruth ­Henriques, Daniel Gibbings, and Mimi So pen missives to their youthful selves ­musing on how they started, where they are today, and all the things they learned along the wayDear Stephen Junior,I realize you’re only 8, but it’s time we sat down for a chat about the birds and the bees and, in this case, diamonds and pearls. Trust me, son, this is harder for me than it will be for you. Take a seat. Can I offer you a cigar or a bourbon? I think I’ll have one.It goes without saying that the birds, and to a certain extent the bees, will drive you crazy. As for diamonds and pearls, though you don’t know it yet, very soon you will develop an unhealthy interest in both. Like most things that are bad for you, the ­jewelry industry can be very seductive. Once you’re hooked, withdrawal can be so severe that very few are strong enough mentally or physically