My neighbors late 2002 B2910 has a serial number in the mid 54000. 55335 should be a 2003. Tractor year is usually set in the year it was sold if it is a current model.
I would be more concerned about condition and hours on tractor.
Equipman, I would like to know the age of my tractor. It is a B6200HST-D, serial # B6200HD50578. Your effort to post this info for me would be greatly appreciated.