Usage patterns
〈人〉はまだ未熟だsomeone is still immature/inexperienced
He is still inexperienced, but he keeps working hard.
未熟な〈物〉an unripe fruit or vegetable
I got a stomachache from eating an unripe persimmon.
〈人〉の未熟さsomeone's immaturity/inexperience (as a noun)
It was an incident that made me keenly aware of my own immaturity.
未熟なりに〈動詞〉to do something despite being inexperienced
I did my best even though I'm still inexperienced.