Career Advice for a Mobile Developer



Hello Sir,
I am a Mobile Apps developer. I have around 4 years of experience in Mobile development. I wish to get into Data Analytics field .
I have started learning Scala, Python and Spark. I have made my way through books.
I am learning everything by own.
1 How much time I need to take to complete all the important collection of technologies in Big Data ?
2 Will industry treat me as a fresher ?
3 I won’t be having project-based experience in this field ,will the HR of companies accept me as a candidate ?
4 Is certification important ? I prefer not to have certifications and apply and crack interviews ?
5 I prefer reading books and learning for COMPLETE knowledge. Is this the right strategy ?
6 Any other advices that I should follow to brighten my chances with the technologies and job ?