Here are two pictures of Roberta from March 1955. As usual, Roberta looks quite stylish. I think the one with the diaper bag was taken before the trip to Florida and the one in South Carolina on their way home from Florida -- this was the beginning of Roberta's talking life and she looks quite happy to be the "oldest."
Roberta - March 1955 - "Ready to go" with Serena's diaper bag
Roberta - March 31, 1955 - Magnolia Gardens, Charleston SC