Do you know any of the parents? I'd err on the side of caution with such an age difference, personally. At the same time, it might depend on the circumstances. For instance my oldest's circle has an age difference of about 2 years, with him being the youngest. It includes his cousins and their friends. So in 8th grade he was surrounded by 8th, 9th and 10th graders. All parents know each other, though. And tabs on these kids is certainly occurring.