My youngest curry leaf plant #5, two years old. It is 19cm (almost 8 inches) tall from the soil level. I just did pinching a couple of weeks ago.
This is its second summer. All I need to do is to cut the plant about a few centimeter (one inch) from its top.
It is nothing, but you might be a bit nervous if it is your very first time to do so.
Intention of the pinching is to increase side buds and increase number of branches for more leaves to harvest. However, this case, only very top new bud is shooting.
since summer here in Japan is almost over, I would have to be patient until next spring for another opportunity while keeping it in warm room inside to overwinter. Ambient temperature should be 20 degree C (70 degree F) as average high for next spring time for pinching.