I felt really guilty but I had no idea when my baby was teething for the first time. One day I put my finger in his mouth and there were two teeth poking through his bottom gum! He hadn't been particularly fussy or upset, it was crazy. He now has 8 teeth and hasn't had much trouble with any of them really.
I do wonder if some mums think there always has to be a reason for them being fussy, so they attribute it to teething. Sometimes it can be other things, they might be doing through a developmental leap or just having a bad day! But there's no way to know that, and I get the feeling that Rhiannon has some control issues, so it's easier to attribute it to teething, which you can do something about.