I'd do it now, since it's never been done since it came off the lot... I did mine after it's first year and found very little grease in the bearings.. Enough to not cause any damage, but not like how I like to see them packed..
I do my own and it gives me a chance to check and adjust the brakes too.
After the first couple of years doing it every year, I've now gone to every other year now because I saw that after MY packing of the bearings, they still have plenty of grease in them, even every other year.. But, the brakes still need adjusting, so that's my schedule.. ;)
Good luck!
Mitch