Thanks, Ravn! Note: the connector is called a 6-pin mini-DIN, and the keyboard and mouse connector pinout charts above show six pins, but some mice and keyboards are made with the (male) connector having only four pins (i.e., with the unconnected pin 2 and pin 6 missing).
Use general age categories to categorize the rabbit. This will give you a good way of starting your assessment. A young rabbit is up to 9 months of age. An adult rabbit is approximately 9 months to 4 - 5 years of age. An elderly rabbit is 4 - 5 years upwards. Some rabbits live to be 10 - 12 years of age.
The age a rabbit can be spayed/neutered depends on when the vet is willing to operate, but for boys it can be as soon as the testicles descend, and for girls it can be around 4-5 months. Vets have their own preferences and reasoning for when they spay/neuter so always ask and listen to why they do what they do.