I hope the following gives some ideas for your speech.  Take those parts or points that interest you.
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Hello friends, TODAY I wish to tell you about my future ambition in my life and the strategy I will adopt to fulfil it.
 
    I want to be a computer engineer, when I grow up.   I want to be an engineer on designing the advanced computers of the latest technology, its components and peripherals.   The reason is that I am interested in the most advanced technologies, fascinated by the electronics and micro level and nano level technologies.  I want to achieve some thing great.

    In order to become a good engineer, I will develop the skills and knowledge required.   I will study my pre-university very well.  I am interested very MUCH in mathematics, physics and electrical sciences.  I want to be a graduate from the BEST engineering institutes in India, that is, Indian institutes of Technology.  Graduation from an IIT gives me sufficient knowledge and skills to reach my target in life.
 
     I will join a good coaching institute that will prepare me for the Joint Entrance Examinations.   I will study with absolute concentration and learn to SOLVE problems logically.  Already I am quite familiar with the components, and the structure of computers and the softwares associated.

    After joining an IIT, I will focus on the current technologies of fabrication of computers, chips and peripherals.  I will take the electronics club as my hobby.  I know that we don't have a good technology in India to fabricate electronic chips and computers.  When I have sufficient knowledge and experience, I will start an electronics manufacturing company in India.  I want India to be like the advanced countries in the East like Korea, Japan, China which manufacture a lot of electronics and export.
 
   I will go abroad and do a post graduate degree in computer (electronics) engineering.  To be able to do this I will appear for the necessary examinations and maintain a good score during my graduation.  I know it is expensive to study abroad, but I will secure a loan from a bank and repay it when I am employed later in future.