Hmm, I haven't tried kissing obviously. I'm only 11.
But kissing the cheeks of my younger brothers is not included...Heheh...
So anyways, in my opinion, you should be kissing at the age of 18 and up. Since, it's the legal age [in most countries] it should be the best age for kissing. But still, kissing is not yet in my mind. I still have to focus on my studies, right?
But unfortunately, some people have other priorities. A classmate is only 11, and already has 5 ex-boyfriends! All of which she has kissed, [b]on the lips[/b]!
Right now, I don't know if she still has one.