I believe this statement has many argues for and against this view, I will be looking at both sides of this argument and producing my view.
It is very hard when discussing Christianity and in which the age of someone is defined a child or adult, in the Christian world, is a child judged as an adult at the young age of 5 or 6? When a child is confirmed at the age of 14 or 15? Or is when you are legally classified as an adult at the age of 18? But who can put the boundaries on faith, religion and your own personal beliefs?
In Marks Gospel we learn that we should have child like qualities, this is telling us that child like qualities is what we need to be a good Christian, Honesty, enthusiasm, trust no matter what the case may be but then on the other hand they may not be spiritually and intellectually developed yet and be able to understand the aspects of being a Christian and disciple of Jesus, they believe in such things as Father Christmas, the Easter Bunny Rabbit and the tooth fairy their beliefs for that is strong.
They have faith in these and great enthusiasm but to their knowledge all of this is real not make belief therefore they can not have the complete commitment and understanding of being a Christian but they can learn and develop into one.
Some may say that Children are more like Christians then anyone because they disciplined, they attended church, say there prayers and tend not to commit crimes and obey by the 10 commandments as adults tend to be able to do that more.
Children such as baby’s cannot make a commitment for life and decide for themselves so they can be baptised and Godparents and parents will help guide you to Jesus until you can make your own decision and choose to get confirmed which is a positive response.
A faith of a child can come from their parents who have faith but then how can these young people be able to understand it unless you have experienced something to believe it, which is the case in many stories, so then… When children have had a life changing experience are they criticised for not knowing how to be a Christian?
Children may be selfish as they need a lot of care and it is all about themselves but they can do kind deeds spend time with disabled people and do kind gestures which is all about being a disciple of Jesus and following the nature of discipleship in the beginning in Marks Gospel.
Based on these arguments I believe to an extent that children can be disciples of Jesus and good Christians because as long as they believe and act as a Christian they have hope and faith in God, and in time their knowledge will grow as they follow the foot steps of Jesus.