Why can't you be in one grade and have friends in another? Do you go to class to socialise? I remember very little socialisation during class past the first few years.
I have kids who have friends in other grades, and kids who have friends in their same grade. We also have an EG ds who we purposely chose not to accelerate for social reasons, and while he's bored in some parts of school, it's worked out well socially and that's been more important to us at this point than the academics (but that's just us and our ds - he's a kid who would rather be bored and be with kids his age than stand out - his words and thoughts - as the youngest kid in class).
I don't think the issue of friends is as simple as thinking that friends are something you "do" outside of class - friends often happen among the kids you are actually in class with every day because that's where you (as a student) are spending a huge amount of your waking hours. Class is also where a student is exposed to age-peer interactions whether or not he/she is among close friends. Same-grade classes usually have lunch and recess together at the same time, PE and art/music etc are with your same grade... so there is a lot of time spent with the same-grade-you're-in kids that's somewhat social even though it's school.
For me (as a parent) - acceleration would have been ok in elementary (socially) but I didn't think my ds would want that in middle school, and honestly I wasn't really keen on it. I had friends who had accelerated their kids as well as friends with children in multi-age classrooms (4th-6th grade), and the 4th graders were hearing concepts (outside of academics) that their parents really didn't want them hearing about or thinking about yet that they most likely wouldn't have if they were in classes with only 4th graders. The friends who had grade accelerated were very much thinking it was the thing to do in early elementary, but once their children were in middle school they were upset about some of the things their children were exposed to around children who were into puberty/hormones/opposite sex earlier than they'd thought about their child thinking about it. Note - I'm not anti-grade-acceleration AT ALL, these are just some things that influenced me based on my parenting hopes and desires. I also didn't want my kids leaving home for college one nano-second before I have to let them go - I love having them here! So.... while I will advocate like crazy to be sure my kids have appropriate subject acceleration... I wasn't so excited about whole-grade acceleration. Now that my ds is in middle school, it's pretty clear that was the right choice *for him*. So anyway - just something else to consider with a grade skip.
Best wishes,
polarbear
