2017 => now()
16-year old => 19 yo
Matriculation => Leaving college
Going college in my father rickshaw/auto => Working remotely
printing 'Hello world' in android phone => Using ThinkPad for day to day coding (still not comparable to MacBook but much better than smartphone :p)
'a shy person' => Attending Hackathons, local events, expanding my network and learning new technologies
Turned down on for "not enough experience" => Receiving job offers via LinkedIn and GitHub
Learning from my couch => Working from my own Home office
Knew nothing => Know something
Just write stupid small apps.
With lots of practice, you will eventually become a great developer. Although, you may never consider yourself that as you should always be seeking out learning more and more.
In the end, the thing matter most is your 'curiosity'. It's your curiosity about 'How things work' which will lead you somewhere...