The teenager made his first competitive start for Celtic at Kilmarnock on March 13, before scoring his first senior goal in the Premiership-clinching 5-1 victory against Partick Thistle at Firhill last week.
The Scotland under-19 international featured in four of Celtic's five SPFL Premiership matches during March, including home games against St Mirren and Ross County.
Henderson said: "I made my first start and scored against Partick Thistle as well, so it's been one of the best months of my life so far.
"I think I've been improving all year because I've been training with the first team since we came back from pre-season in Germany.
"I'm very grateful to the manager Neil Lennon for giving me the opportunity and I've been able to pay him back with some good performances and a goal."
He praised skipper Scott Brown for influencing his career at Parkhead, saying: "Scott has taken me under his wing and he's been unbelievable. He's always talking on the pitch and it's brilliant to play alongside him.
"He's captain for club and country and he's been a great mentor to me off the park as well, so he's someone I'd like to model myself on."
Despite his elevation to top-team duty, he reveals life has not changed for the Henderson family.
He said: "My family keep me down to earth - my wee brothers and my mum and dad."