Hi Alex, you mentioned light roasted. Are you sure it is even roasted? The grassy note present seems 2 point otherwise. The tea might be baked at the last stage 2 dry off the water content in the leaves, but roasting it would change its note 2 deep floral with a light roast.
1stly, do you use a gaiwan or a clay teapot to brew it? I suggest a porcelain gaiwan.
2ndly, how much leaves do you use? I suggest just enough 2 cover the base
3rdly, bring the water temperature 2 85c & no higher
4thly, pour the water from the side of the gaiwan 2 3/4 full
5thly, leave the gaiwan open till you are ready 2 pour it
Hopefully this gives you a better brew, or you can store the tea away & taste it again in about 6 months' time...
Kevo