Do not buy children’s encyclopaedias. If you wish for a career in any deep science stream, encyclopedias, documentaries are a mode of entertainment rather than learning. Being good at Physics, Chemistry and Maths would take you long way ahead. However you can begin by reading these books to satiate your thirst for astronomy.

Stephen Hawking’s books:
- Brief History of Time
- The Grand Design
- The Theory of Everything
Hawking talks about the history of the universe from The Beginning to study of astronomy and universe in the ancient ages, to current explorations in this field. The way of writing is really crisp and would be great for your age.

Carl Sagan, Cosmos
This is another book loved by teenagers and retirees alike. The book was written during cold war, and the writing style is quite engaging. Sagan ties together history, philosophy and science and connects them with recent discoveries.

Stephen P. Maran, Astronomy For Dummies
For Dummies books provide a very good overview of a vast topic. He covers the Sun, The galaxy, The Universe, Big Bang theory, quasars, asteroids and extraterrestrial intelligence in an engaging manner.