I'm a boy. I was born with a full head of platinum blonde hair, and
i'm now 16 1/2 and my hair is still the same light blonde color. I've
heard that blonde hair is supposed to darken as one ages, but if that
was the case, wouldn't I have seen a change by now? Is it possible
that my hair won't darken like the others? Is there still time to
darken, and if so, how dark could I potentially get... I mean time's
kind of running out, i'm almost done changing and growing!

Regards,
Tim

Hello Tim,

I?m the opposite of you. I?m a blonde whose hair has darkened over
time and I wish it would have stayed the light blonde I was as a teen.

Anyway, the answer is just that your hair might not turn. Many
blonde-haired people do have their hair darken, but not all. However,
this is a process that can occur over your whole lifetime, so who
knows, it may happen 20 years down the road.

Hair darkens because our genes get essentially turned on and off by
proteins called transcription factors (TF).

I found a website explaining this with the idea of a recipe.

?TFs are called activators when they turn genes on. Activators work
like a bookmark that leads us to the recipe we want. Activators turn
genes on by leading the cellular gene-reading machinery to the recipe.

TFs are called repressors when they work to shut off a gene.
Repressors are something like a paperclip that sticks the pages of the
recipe together so that we skip right over them in our cookbook.
Repressors turn genes off by making the recipe invisible to the
cellular gene-reading machinery.?

?Hair and eye color can darken over time because the respective genes
are turned on. This can happen either by an activator being turned on
or a repressor being turned off.?
http://www.thetech.org/genetics/ask.php?id=63

Looks like you just haven?t had the right recipe yet in your genes to
darken your hair. Give it some time or just be happy with the blonde
you have now. There?s always hair dye as well. Ask your stylist to put
in some ?low lights? This will give you a sandy blonde effect and
lessen the shock of the bright blonde.

Google Search Used:
blonde hair darkening
://www.google.com/search?q=blonde+hair+darkening&hl=en&lr=&start=10&sa=N 

If this answer requires further explanation, please request
clarification before rating it, and I'll be happy to look into this
further.

Nenna-GA
Google Answers Researcher

Oh dear, you should dye it.  Yellowhead just will not do.  Just not
Goth-style jet black.  Alternatively, a crew cut will reduce the
blonde impact.

Tim, sweety,

You won't be fully grown until you are 19 or so. Don't worry, lots of
ladies love blonde guys!!

Steph53