What age should you start to shave?

When you are at least 11 12 13 sometimes ten check if they have hair in the bikini area.if they do its check 1. next is arm pitt hair/leg hair. that is check 2 is there age. now if they hit there period well or about to let them shave if they will start there period its whan they get cramps around there waist but whole different question

I started shaving my legs when I was 10 and then my armpits at 11..