I'm 34 and I already lost half of my teeth. By 40 they'll probably all be gone.
It's definitely genetics, but also very much the lazyness in my youth that caused this.
If someone in their twenties reads this: Brush your fucking teeth, seriously. I had a phase in my life where I was living with constant pain for almost a year and almost went insane. Nobody should have to live like this.
Also don't brush your gums too hard, I did that a bit when I didn't know better, and my gums receded slightly. Turns out those things don't come back. Make sure you brush that area though!
My electric toothbrush was an amazing investment. It flashes red lights if I press too hard while brushing. You'd think after 10 years of this thing that I'd develop an intuition about how hard to press, but it still yells at me to back off all the time. It's made a huge difference for the health of my teeth.