I'm in between 6'1 and 6'2. I'm 16.
Now I weigh 170.
What is the average weight for a kid my age and height?

The "average weight method" is a wrong method that is very commonly used and i don't understand why. For example some bodybuilder your height 6'1-6'2 is 250 lbs ,he has 8% body fat and he is ALL MUSCLE with a rock-hard 8-pack that can be clearly seen, while another guy, is also 6'1, 6'2 and 200 lbs however he is flabby and doesn't have muscles and has a higher body-fat level like 23%. If you look in the average height-weight scale you are in the average level but the only thing you need to see is the bodyfat percentage. Ask a doctor to calculate your bodyfat level or use some of the other methods to calculate it.

I was just curious. Thanks.
What is a normal body fat %?
I'm assuming %5 would be awesome.
But can it be to low? Like is %1 unhealthy?

Yes, 1% is unhealthy. For men, 2-3% is essential body fat.

Anything below 7 depending on genetics is practically impossible to maintain. When you see body builders in competition and they're at 3-5 % they stay like that for no more than a week or two at a time, they have to seriously dehydrate themselves to look like that. Same for the super lean people you see on magazine covers. when they're not working the add fat you should see some of the bodybuilders during the off season, huge pot bellies.