Contarary to the above reply i would say that it's ok if you hugg of kiss some girl of your age until and unless you do not indulge in any kind of sexual activity.
Let's suppose a situation when your sister of your age had achieved some tremendous achievement in life or if she had won a scholarship in college or school, will you not like to hugg her or kiss her to show your warmth and affection and to show that your are really very happy at her achievement.
You are so right. You said it correctly:
So i dont think that if an Amritdhari Sikh loves someone he should not kiss or hugg any girl but the bottmline here is that this act should be to show the affection and warmth in your relationship but not any kind of sexual advance.