First of all you have to see the history of the same in the family as to if your fathers hair turned grey in early days of his life.
Second is it's a normal tendency in some individuals to have the grey hair starting early in their life.
So stop worrying and start accepting
Next Steps
Try not to stress yourself much over this as more the stress and more this increases. Secondly be cautious in applying any hair colour over the same
Health Tips
Biotin is very usefull and mediated hair colour is your only solution