Do you grow black hair on your arms before your about to hit a major growth spurt?

I've recently noticed black hairs on my arm that are longer than the other hairs on my arm growing. And hair on my cheek which was never there. I turned 15 feb. 26, and i was wondering am i about to hit a major growth spurt or do you hair after your hit it?Do you grow black hair on your arms before your about to hit a major growth spurt?
after i hitDo you grow black hair on your arms before your about to hit a major growth spurt?
You'll just have to wait and see.