Thanks for reaching out to me. It is very nice to know that you are interested and fascinated by subjects in the mechanical engineering field. Being in India, your family's apprehensions regarding your choice in engineering is not completely baseless. Due to a variety of reasons, even today in India, mechanical engineering is not considered a women friendly engineering stream and it is perhaps due to this general conception that your family perhaps thinks it is tough to find a job.
The real question you need to ask yourself is, what is YOUR priority in life. Do you think it is more important that you find a job 'easily' or are you willing to put in hard work when the going gets tough? Do you know what kind of job/jobs do you envision yourself doing after 3 years. Do you want to be an automobile engineer, want to do something in fluid mechanics, do design engineering, robotics? Do you see yourself working in the IT industry? Is that something you could potentially develop an interest in?
I would suggest before you make up your mind, find out if your college provides assistance in finding jobs in the mechanical engineering field, if not, what can you do yourself to get a foot hold in the industry? There are a lot of avenues - working in the govt sector area, BHEL, HAL, NRSA etc are examples or working in the private sector areas, TATA motors, Chrysler, Nissan etc. Find out what you need to do (write entrance tests, apply online etc) to find job here. I will not deny that while computer science itself is definitely as challenging as the mechanical engineering, in India, finding a job in the IT service sector is relatively easier since the demand for talent is quite high. But if you are willing, motivated and consistent in your efforts, you will definitely make it.
If you have more questions, feel free to reach out to me via email and I will be glad to help you out.