First oil change at 5K, excellent idea! I would have dropped the factory oil at about 4K, but 5K is ok. Of course MINI wants you to wait until it says change is due. Always safe to change your oil and check your oil levels at reasonable intervals, new MINI, old MINI etc. etc.
MINI will also change your oil, for the free oil change, after the anniversary of the purchase of your car. I got my first free oil change around 5000 miles just after I had my car one year.