HELP! my plant is about 3 week the leaves on top turning yellow but looks healthy

my plant is 3 weeks outdoor gets enough sun although at one point it raind twice and got a little bit of rain even though it didnt need it from the first rain idk its just the top leaves turning yellow but no curling there sticking up looking healthy , so like wtf is wrong with it is really why im asing cuz i mean its still growing too.

Pics would help as well as other details.

Soil type (soilless medium)
Watering regime
Nutes (if any as of yet)
Light hours

Sometimes the new growth at the top will be lighter colored and will get greener as it grows