There are a lot of issues with child marriage and it is not something I would openly support. Although one of the main issue with child marriage is similar to that of child acting; which is the child doesn't decide, the parent does. The co-star of ICarly recently spoke out against her role in the show stating it was not something she wanted to do but something forced on her by her mother. Children are not given a voice in our society when it comes to their own freedom.
But no matter how you feel about the issue it was probably not a good idea to try and debate the issue with the actress on social media. She probably feels very strongly and passionate about it. You're just asking to have your balls busted.