Can i be sued for defarmation of character?

Hi, i am 17 and have recently seen an end to a court case. In this court case I reported my grandfather for 2 years of ual abuse. The court case ennded and he was found guilty and now has a suspended sentence (due t his age). Now I have heard rumour that my grandmother (his husband) and a cousin of mine are looking into sueing me for defamation of character against the 2 of them. My nan for obvious reasons and my cousin because a rumour went round that she too had been abused by my grandfather, and they were told i started it. I am now petrified I have just overcome one court case, standing in court when I was 16 and really dont want not go through another experience simular. I have read online that in the UK they can sue people as young as 16! can someone please help me out here with any advise x