Unless you have a very good reason to change (need a bigger car) i'd just keep the mini. otherwise you're paying a wedge of cash more than is needed just for the sake of changing early.
The arse has totally collapsed out of the mini market. Got a friend that works for Audi and she says they regularly get people with minis looking to swap for A1s. She says they can never make the finance work as they are always upside down on the finance.