Child marriage is a great hindrance to progress as:
one of the main reasons is that when children (most probably girls) are married at an early age their access to basic education is blocked
due to which the nation will never progress.
other reason is that the children have the responsibilities of their families on their heads & they are unable to enjoy their period of and they are kept away from all the basic facilities that a child gets at his/her child age.
hope it helps