Software Engineering

Hello Vikash,
Software engineering is the application of engineering to software that includes documenting the requirements of the software through application of basic design principles. Software engineers also learn to analyze and design alternatives keeping in mind the utility of the finished product and whether the final product meets its requirements. At the same time they are also trained to realize the safety, reliability, cost-affectivity and functional aspects of the software.
Software engineers learn to research, devise, experiment and maintain software systems as per the requirements of the client. They are well-versed in computer programming languages and applications.
You can join small and large-scale business establishments, government agencies, and non-profit organizations as a full-time employee, on contract basis or even as a freelancer. One can expect various roles in an organization that include analysts, architects, developers, testers, technical support, managers and also researchers.
Core Subjects:
Mathematics
Chemistry
Basic Engineering
Computer Literacy
Physics Laboratory
Engineering Graphics
Biology for Engineering
Principles of Environmental Science
Material Science
Digital Computer Fundamentals
Computer Organization and Architecture
Data Structures and Algorithms
Software Engineering Principles
Object Oriented Programming
Microprocessors
Software Design
Computer Skills
Discrete Mathematics
Computer Networks
Industrial management and economics
Software quality management
Web technology

Start learning C, C+ or java.or can start either with C or C+. There are several video lecturers available on YouTube if you are not comfortable with textbooks and it really doesn't matter that you should first join college and then start learning software languages. There are several students I know who are mastered in this field before joining college. But it really takes serious dedication with lots of frustration.
Try to practice on coding websites like HackerEarth or HackerRank then you will learn how to practically implement your codes.
Have some basic knowledge of computer Architecture, like how it works, how data or instructions flow. It's also available on YouTube.
There is not only one field to learn in software Engineering, if you are pursuing your B.Tech degree, you must have known about this, if not u will. New sectors are emerging day by day, but the concepts do not change.
Language changes like people now switching from php to django.
So you should learn at least 9-10 languages (doesn't matter if u are mastered or not) but you must master at least one language, and that's the key to be a programmer and hence Software Engineer.
It's all about programming and coding.