When did the high school student Philo Farnworth invent first television?

Philo Farnsworth did not invent the television while he was a high school student. While he *conceived* of the crucial electronic television system at a young age (around 14), he didn't build and demonstrate a working model until years later, after leaving high school and pursuing his inventions through various means, including further education. The first successful demonstration of his electronic television system was in 1927.