(CNN) - Jenna and Barbara Bush know a lot about growing up in the White House.
The twin daughters of former President Bush were 7 when their grandfather, former President George H.W. Bush, was inaugurated, and 20 when their father became president.
Like their dad, who left a note for President Barack Obama, Jenna and Barbara Bush wrote Tuesday to Obama's daughters about what to expect in the weeks and months ahead.
"We also first saw the White House through the innocent, optimistic eyes of children," the twins wrote in an open letter published in Tuesday's Wall Street Journal.
The twins reminisce in the letter about important events and historic moments they were able to be part of in a presidential family.
But the Bushes also tried to prepare Sasha and Malia for some sobering truths.