There are no rules that I know of for how close you should be and how long a kiss should be. Although at 13, I would recomend at least a few inches between you when you dance. As for kissing, I think a quick smooch, a pucker, would be all you should be doing at this age. 13 is too young to be getting too serious. At least if I were your mother, that's what I'd say.
And if you didn't listen to me I'd handcuff you to the bed post till your in your 30's.
It depends on the dance and how long you have known the guy. If you have known him for 1+ years, and you are in an area where others are not, maybe 2-3 seconds? If you barely know him i would refrain from kissing. If you are in a public area and you dont want to go public ( with your relationship ) don;t kiss and say you are dancing as friends. Careful however who you choose to kiss..... And on the how close you should be.... And inch to the width of a magazine if you know him good.... If not 3-5 in would be better
Whenever i slow dance, like every single time, im like poking her
My advice is to go with the flow, live in the moment, see what happens. Enjoy!