The biggest problem the jump ahead caused for me was that not only did I lose all my friends, but everybody in my new class hated me (especially the cleverest boys) -- because, with hindsight, they felt threatened by having someone a year younger as their rival. There was another boy in my class who had also been put up a year, and I now realise he wasn't popular either -- that, of course, didn't cause us to make friends with each other.