Body changes every 7 years and after having a baby

Liz

I’m 24 and I have a 4 year old. This is the very first period I’ve had with back pain and tender breasts, I’m also non stop hungry (I usually don’t eat much on my period) I asked my mom but her answer to everything is “Your body changes every 7 years or so and after having a baby”. Is it normal to develop new period pains and aches and symptoms after so long? Has this happened to anyone else?