What examples can you find in lincoln’s address of organizing ideas into groups of three?

I'll assume you mean Lincoln's famous Gettysburg Address.

From that address, here are some examples of organizing ideas in groups of three:

The main example is the overall 3-part outline of ideas in the speech.

Another example of three-part statement of an idea comes in the third and final paragraph of the speech.  Lincoln said, "In a larger sense, we can not dedicate -- we can not consecrate -- we can not hallow -- this ground. The brave men, living and dead, who struggled here, have consecrated it, far above our poor power to add or detract."  Notice how Lincoln uses three phrases to emphasize the idea that any words spoken were not the true honor of this place, but the valor of the men who gave their lives there that had already hallowed the ground at Gettysburg.

depends on the age of the teen, many believe by the age of 16 a person should know the strong difference between right and wrong along with the difference between risky and immediate death. swimming with sharks might be dangerous but swimming with sharks while bloody meat is attached to you is just insane. even more if you have no idea what you're doing. however, no matter the age, as long as the person is skilled enough and has the mental and physical capacity to control their actions doing whatever sport they put their mind to is all that matters.