Is your frontal lobe fully developed?

I recently joined my school's science/math club.
For our main objective we must create a presentation that will be presented at one of the local colleges.
I choose my science project to be on the human brain, because I've always been fascinated with how others think, and act.

So today I'm going to give you a lesson on the brain.
First, let us start with the basics.
The human brain is made up of eight individual parts.

• The Frontal lobe
• The Central sulcus
• The Pariental lobe
• The Occipital lobe
• The Temporal lobe
• The Cerebellum
• The Olfactory bulb
• The Spinal cord

Each one of these parts of the brain are made for different, yet, slightly similar things.
The main one I will talk about in this blog will be the Frontal lobe.

The Frontal lobe is what causes/allows emotions, problem solving, planning, parts of speech and so on and so forth.
Now here's the real kicker, and pay attention because this might come in handy in the future!

The average frontal lobe does not develop fully until around the ages of 20 or 21.
Full maturity comes at right about that age. More reasoning, and more thinking.
Should I do this, and what will happen if I do that?
You think less about these kinds of things when your frontal lobe isn't developed to the fullest.

----- Now for what I think about this.
I think that the frontal lobe develops more quickly after childhood trama.
Take notice that after many men are sent out to war, they come back with a colder stare, broader shoulders, and more sense to their actions.
Have you seen a lot in your life? Have you been through something that haunts you even now?
~ For these things to react with what you do now would only mean that the thoughts that are flowing through your brain and morphed into a more adult-like stature.

Am I sensing a Hypothesis?