so u two have been together a year and u havnt kissed, WOW. but there really is nothing to be nervous about, since he already been kissed he might know what he's doin, so all u really have to do is take it slow, and think of kissing as dancing, he'll be leading and ur following, so whatever he does copy him and you'll be fine, so dont stress about it, and odds are that he's nervous to.
