I was driving at age 10... I was also carrying a firearm and hunting alone at that age...
I had free reign on the lake with the motor boat at age 9... wearing a life jacket was not required...
I had my first mini-motorcycle at age 7... no adult supervision was required when I rode it...
I rode my bicycle on the streets of the neighborhood, several blocks out'a sight of the house, before I even started school... weren't no bicycle "helmets" then neither.
My oldest son has never shown any interest in saws and such, but he was shooting a .44 Magnum with a modified handle at age 6, I gave him his first rifle at age 7... he practiced with it on our shooting range unsupervised.
My youngest son hasn't shown much interest in firearms, but he's all about power equipment. I gave him his little ATV just after his 5th birthday, and he's been riding it all over the property for three years... including in the woodlot out'a sight of the house. He "helps" with any maintenance or repairs to it... if he didn't "help", it wouldn't get done, that ATV is his responsibility, not mine. He's been running the log splitter since well before that, and even taken a few turns on the old grass cuttin' machine. He has a keen interest in the saw, but at age 7 he just don't have the strength to hold it yet... maybe next year.
So-called "maturity" is more about personal responsibility than anything else. I teach my kids that they are, first and foremost, responsible for themselves. Actions have consequences, it's your actions, not your parent's decisions, that determine if those consequences are positive or negative. Show me personal responsibility for your actions (including the bad actions)... and I'll allow you more rope. As a kid I was held personally responsible for my actions, no matter what they were... I was never allowed to make excuses, and no one ever made excuses for me. The "heroes" I looked up to were an example; I provide that same example to my kids, and I hold them to the same standard... but, now-a-days, I appear to be the minority. I really get tired of the blaming something other than the person... the excuses... and saying something like, "You can't blame him, he's just a little boy", does a huge disservice to the man the little boy eventually becomes.
There ain't nothing wrong with allowing kids to be kids, they need that also... but there's a time and place for everything.
*