My honest recommendation would be to read the book Volcanoes by the late Peter Francis and Clive Oppenheimer. It is an excellent overivew of the subject written in an enthralling and captivating way, that is sure to get you hooked. I am afraid that if this book doesn't peak your interest then volcanoes and related phenomena probably aren't for you! The latest version of this book can be bought used for ~£20 or an early version written by Peter Francis only for ~£4 used on websites such as amazon. Having read this book you will discover that the world of volcanoes and volcanology is extremely diverse and ranges from the centre of our planet, the bottom of the seas and even to distant planets.
Bit of a random post, I know, but I would have loved someone to point me in the direction of this book at the age of 16, it's still a good read at any time!