My DS is starting in K-1 in the fall right after turning 5 and will officially be a first grader at the semester. He's working at a second/almost third grade level. Although we will be doing Independent Study based homeschooling we want the skip and that's something a lot of people just don't understand. If you homeschool you can do whatever level of work the child is at, grade level doesn't really matter for curriculum.
Our reasoning is that we have found that when people ask giving a grade is easier than giving his age. When someone sees him reading and asks his age we just say he's in K (he's being homeschooled K already, long story). That gets an "Oh! well that's pretty impressive for K." If we say he's 4, we get shock. In our universe he is normal. We're doing our best to shield him for as long as possible from adult responses that would make him think differently. That's really our main reason for the grade skip since the curriculum isn't an issue.
Does this make sense to any of you? Do any of you do similar things for your kids?