How can I so sure enough to choose which branch of engineering ( interest) like how did u know this is the branch of eng I'm interested in???

Hi, firstly take it easy. Secondly go grab your book and pen. Now, what you can do is write what you wish to be in next 10 years. For example, in next ten years I see myself as a successful PhD holder in marine. Do not write that you wish to be a billionaire, that does not count. Later go search for jobs currently do some market research, try to find some similar people on LinkedIn and understand what it took them to be there. Once done that write the pros and cons of getting that degree. In this example pros are hefty salary and a dream of becoming one. Cons are no family contact for a long time, sea sickness, male dominated. Once you are done with this. If you are not sure of a specific branch do not go in depth. Example, If I am not sure about Marine and I have second thoughts about it then I will choose Mechanical Engineering that way I have more options for the future. When you are done with the whole list of it weigh your pros and cons is going to be worth it? Is the market stale? Are there good job opportunities? Write down answers to such questions and ask yourself where you are ready to compromise. If you have more than 1 list cut it short to 2 or 3. Now select your first priority search some good colleges that are known for your branch and they have extra curricular activities related to what you wish to do. And this is how most of us trim our choices. Hope this helps. If you still have doubts feel free to comment.