Mine has been on the road for almost a year and a half, I'm at about 17,000 KM and the dealer has changed the oil three times in that period. Nothing else has been done. That said at the bottom of my last invoice they recommend in 4 months (or 8,000K) a comprehensive service for $198 + tax. They don't say what its for, but I'm sure its the usual, check/top up fluids, lube door hinges and locks, inspect brakes/lubricate as necessary, rotate tire (if needed) etc.
My dealer (Freeway Mazda) shows this as SERVICE B
Recommended every 24,000 km or every 12 months
Inspect and clean brakes discs and pads, front and rear
Lubricate caliper rails/pins
Inspect A/C operation
would also include SERVICE A:
Recommended every 8,000 km or every 4 months
Replace engine oil; Replace oil filter
Inspect function of all lights
Inspect brake fluid, power steering fluid, washer fluid and coolant level
Inspect all tires - inflation and wear
Lubricate all locks and hinges
Rotate tires (priced separately)
It won't void your warranty if you don't do it right away, but it is your responsibility to maintain your vehicle, you should probably get it done, but its not critical to do right away, I'd say you can safely delay several months without harm.
The one that is important is to lubricate caliper rails/pins, this will keep the calipers moving smoothly and help prevent uneven wear of the brake pads and reduce noise (squeaky brakes). We also have a Honda Civic and I get this service done once a year otherwise the brakes make clunking noises when applied. Rotating tires is also a good idea if you're at 20,000km and its never been done.