Is it normal that my mom became angry when i shaved my arms?

This is something that happened when I was 17. As of now, I am 19 years old. When I was 17, I shaved my arms because I was bored and I had nothing else to do. I was also curious about what they would look like and how they would feel. The result was that they did not look or feel very different after I shaved them because I did not have much hair to begin with. Also, the hair did not bother me at all. I only did this out of boredom. I did not tell my mom about this, but she noticed it herself a few days later. She felt my arms and became angry. She said, "This is completely unnecessary. Could you not have invented with something better? I hope you don't get a rash." It came to pass that I did get a rash that took a week to leave. My arm hairs took a month to grow back completely. I never shaved them again after that though.