Special Note: Please note that this scenario is meant to be read as entertainment, not as an accurate prediction of the future. Also note that the viewpoints and opinions that may come across in this scenario are not necessarily the viewpoints and opinions of the author.
The teenagers of the 22nd century will have the exact same rights as adults thanks to matriarchy, the Singularity (and its role in increase human intelligence and levels of enlightenment), and erudite forms of music replacing rock and roll music. While having the same rights as adults, these teenagers will deal with classes at school that allow them to learn from each other, similar to the learning method used by Wikipedia users/editors. The teacher simply becomes the moderator; akin to a similar role on Internet chat rooms.
Less intelligent teenagers are content with basic studies, becoming a househusband and changing their kids' diapers while their smarter peers will colonize Mars in addition to other planets and galaxies. It will become common etiquette for a man to adopt his wife's surname in marriage by the end of the 21st century if he has no post-secondary degree and/or a career in a certified profession (athlete, doctor, lawyer, etc.).
Delinquency will be eliminated because teenagers are not treated worse than convicted felons or military soldiers. By the year 2105, it will be declared by the laws of the United States of Earth that childhood legally ends when a person begins puberty, not at an artificial age barrier set by a paternalistic capitalist society. Whole new avenues will emerge, but teenagers will almost exceed the standards of that time period.
Love and romance will be declared redundant as the government develops an AI system that automatically appoints two local people of the opposite gender to marry on their 21st birthday. Both spouses would share common background along with belonging to the same socioeconomic standing and political preferences. This will basically nationalize the services that a website like EHarmony.com does now for Americans and makes it mandatory.
Free from the bonds of conservative tyranny that has held them for more than a century, teenagers will become low-level politicians (i.e, aldermen, mayors, Members of Parliament), poker champions, horror movie fans, breadwinners, corporate executives, and eventually wealthier than their parents. The big three industries by the year 2050 will be in genetics, robotics and nanotechnology; the smallest GNR firm will hire more people in a year than the biggest manufacturing company by the middle of the 21st century. Most movies made prior to 1990 that were rated PG-13 and R will be re-rated NC-12 and PG-13 respectively due to society becoming more lenient towards horror violence by the year 2050 (but not towards sex outside of a marriage situation).
Unaffected by the events of the previous (21st) century like 9/11, The Second Dark Ages, The Second Cold War, the Great Recession and other horrible events, these teenagers will live in a world where jobs are guaranteed and everyone has money to pay their bills and weekly groceries. Autism will have been wiped off the face of human civilization for several decades. However, Down syndrome and Fragile X syndrome will linger on even deep into the 22nd century.
While the movies of the 22nd century will be mostly family-friendly, horror movies will make a comeback after extraterrestrial colonies such as the Lunar Protectorate and the United States of Mars become self-sufficient enough to trade amongst each other with little-to-no supervision from the Earth's government.