Career Advice

I am currently working as an Oracle ERP(Consultant) having over 7Yoe, thinking of switching my career in Big Data space, appreciate people’s suggestions viz., where do I Start with on learning? there are wide expectations for Big data positions - companies expect you to know lot of things viz Spark, Java, Python.. How do I overcome my shortcomings and make them believe that given a chance I can learn these things? I am good at SQL, PLSQL, some Java, just doing some training on Python. Highest Degree: MS in Information technology from a US University Also my interest is in getting a Full time rather than consulting - I am on H1B where I want to avoid the visa hassles. Thanks in advance!