I recieved a citation for theft under 50 dollars should I plead not guilty

This was from walmart I was there with my two year old son first I bought a phone from the electronics department then went to look around I grabbed two toys for my son and two makeup for me as I was looking around my son was putting some of the things in the walmart bag he does not know any better he is just a boy as I was going to pay I saw that he had put the big toy in the bag and I took it out and payed for it I completely forgot about the other items as they were small and I couldnt even see them.. at the door the securities came and asked me to assist them to the office I tried to explain what happened and they told me that we know you saw him and if I put the child into this cps can get involved and say I am teaching him to steal should I fight this I know I am not guilty I really do not want this on my record but my son is to important to me is this true about cps getting involved this was just an accident? Please help me