The humanity's history is full with children and young prodigy. Mozart began to compose music from 5 years age. Galois inherited the humanity a world of new numbers (the complex numbers) little before his death at 20 years. Avicenna graduated from medical doctor at 18. Steven Spielberg began its career at 23 years old and Bill Gates was the richest man from the world at his 37 years old. They were some examples.
It is common that several people could be discouraged when they turn to see around them and compare themselves with other people who reached their goals younger than them.
Then, most of the people think that some goal is not for them, they say ‘it is no longer for my age’.
Other people, simply, do not give up.