Teen star Jamie Lynn Spears, 17, is expecting a baby girl on June 29th. Apparently Lynne Spears, mother of Jamie Lynn, was overheard telling a friend that this baby will be her first granddaughter. Grandma Spears already has two grandsons from her oldest daughter Britney—Sean Preston and Jayden James—who are approaching their 3rd and 2nd birthdays, respectively. The insider tells Life & Style magazine: “I heard Lynne talking about Jamie Lynn’s baby. She said Jamie Lynn and the baby’s dad [Casey Aldridge] were so excited when they found out it’s a girl.” The source went on to say that Spears has been purchasing tons of clothes and is going to decorate the nursery in white, black and yellow. Although both Spears and Aldridge are excited for the baby’s arrival, reports are saying that Casey is a little nervous about having a daughter—fathering a Spears girl is a big responsibility!