GnarlyCow. You are in the same position that
I was last year in May. I bought a 2000 328i with 52350 km
on it and the service counter showed about 19000 km left.
I only put 7000 km on it last year before I stored it. I still
changed the oil last summer and again this August. I would
not go the full distance which is 25000 km for an oil service.
If the car is stored, then change it soon before winter and
then change it next year. If your going to drive it through
winter, I would go with 6 month intervals. Change it around
November and then again in May.