Public displays of affection are acts of physical intimacy in the view of others. This can range from a closed-mouth kiss between new husband and wife at the conclusion of a wedding to teenagers groping each other in a Brazilian nightclub. Whatever your definition of PDA, some people are comfortable with it and some are not.
If you happen to be dating a woman who prefers to restrict intimacy to the bedroom, but you’re a fan of holding hands and kissing in public, then the two of you are going to have to come to a compromise.
Respect her comfort level, but suggest that the two of you keep PDA to a peck on the cheek or light touch. Maybe once the relationship progresses, she will feel more comfortable showing her love for you out in public.
Just remember an old quote by literary critic Barbara Johnson, “Love is what makes two people sit in the middle of a bench when there is plenty of room at both ends.”