Am a post graduate in mathematics and; have 3 years of teaching experience.is it a good idea to change my profession and join IT field.

Hi Mahalakshmi,
You could choose to pursue a career in Computer Science, as you will agree that Mathematics & Computer Science have great co-relation. But before that, I would ask you to question and find the answers for yourself & introspect.
Why do you want to shift and move towards Computer Science?
What is the driving force behind it? Money or Passion?
Do consider 'internship' opportunities, to get a flavour a Computer Science, before you take up a full-time role.
Which area within Computer Science, which you can relate with Mathematics, so that can pursue it taking advantage of your teaching experience as well?
I hope the above questions will help you make a great decision.
And most importantly, never regret any decision, once you have taken.
Good luck with your choice & Best Wishes!

You can change your profession irrespective of you being postgraduate or even PhD in a field if you are convinced that you don't want to end up doing what you are currently doing for the rest of your life. No matter what age you are or how qualified you are if you think that you can enjoy and do much better in any other field which for you is the IT field, you should go for it. If you like doing what you do, you will be successful and more than that you will be satisfied, but if you keep doing just because you attained a degree in that but don't like it then you can be successful, but you won't be contented. When students enrol in any graduation course, their decision is based on so many irrelevant factors (their friends, family and societies opinions about the course, the most popular course, vacancies in colleges and so on) but their interest. Some of them go on to do post-graduation too in the same fashion. The point is just because you didn't realise your interest earlier you shouldn't continue doing what you don't like forever. Lastly, nobody but you can honestly answer this question for yourself. Different people have different opinions. Only you can either prove them right or determine them wrong depending upon how you feel about it and how you take action in future.