Kylie Jenner was stricken with postpartum depression that lasted a year after her first teenage pregnancy. The reality TV star, 27, had daughter Stormi, six, when she was only 19, followed by son Aire, two – both of whom she shares with her 33-year-old rapper ex Travis Scott – and has now opened up about the devastating impact of early motherhood. Make-up mogul Kylie, now dating actor Timothée Chalamet, 28, told British Vogue: “Stormi wasn’t planned. It happened, but obviously I knew that I wanted to have her. I wanted children so bad. “I was 19 when I got pregnant, 20 when I had her… it was…