X.O.
I kissed a boy in my kindergarten class, nearly 28 years ago. After that, I didn't kiss another boy until I was 17, then 19, and then 20--and then I married him. It isn't a huge deal, but you should tell her that she is only allowed to kiss people in her family, and model the type of kiss that you find acceptable. For my husband's family, that is a kiss on the cheek. For my side of the family, that is a quick peck on the lips.