How do you get cf and at what age do symptoms begin to show?

From birth: Cystic Fibrosis is a genetic disorder that someone is born with. Symptoms are usually seen in the perinatal period.

Recessive genes: People inherit a pair of genes that causes CF, one from each parent who themselves are not affected because they have only one defective gene. Symptoms can present at birth, with a bowel obstruction from sticky poop, later in infancy with a variety of symptoms or in childhood. This all depends on a variety of factors related to which defective genes are present.