Changing the gearbox oil, especially on a car of its age, wouldn't go amiss. Perhaps it has had an oil change in the past and the thin, Honda fluid, has not been used. Or the gearbox may have become noisy (like mine) and a 3rd party additive has maybe been poured in.
I sometimes find reverse isn't the easiest to select, requiring the clutch to be lifted and depressed for a second time before it will go in.
Even noisy Jazz gearboxes are supposed to run for ever, so I personally wouldn't get too concerned about it.