"I only go down if ya keep ya grass cut"

Today I mowed my granny's lawn (Not a euphemism). As I was cutting the grass it occurred to me that this was the first time I had ever used a lawnmower. It was the first time I had ever EVER mowed a lawn. I didn't know if it was strange or not to be in your 30s and never cut grass before. I felt like an adult. It also felt nice to be doing something outdoors and something for my nan. It was kinda enjoyable. I might do it again, soon, how long does it take for grass to grow back?