ok im 16 and my brother had full grown side burns my age i need to know if i should shave so my hair gets thick or jest not shave that area i dono so if you can help tell me
Patience is the key. Contorary to popular belief, shaving the area will not make them grow faster, thicker, or at all. That's all decided in your genetics.
Give it another twelve months.
Just put your razor away: When they start to fill out and get some length, SHAVE them to get rid of the 'young' hairs.
They will grow back as you want them
Its not uncommon to not have "full" sideburns at 16, patience is your best answer... You only need to worry when your like me...
I'm 25 I only grow a very light beard around my chin and mouth, so light I need shave only once a week... plus my sideburns are the sum total of about 6 hairs...
Blessing or Curse... u decide...