Random stutter started a few days ago

Random stutter started a few days ago Randomly, a few days ago, I started stuttering. It's pretty mild but gets worse when I get stressed or anxious. I'm 13 and haven't bumped my head or had any emotional trauma recently, but I do have social anxiety. I also have this strange feeling that I'm faking it? I've tried to talk normally and it doesn't work very well, but for some reason I keep telling myself I'm faking it. Any clue what this could be about? How do I ask my mum about it? Any help appreciated.