Actually the whole depends on you , basically it is not appropriate to shift companies so often. But if you do not find the project or the environment of your present firm good enough then you can move to any other firm as per your choice.
But make sure you should be ready with some of the questions from the interviewer side because he will definitely ask you about your previous companies,
- why you switch so often?
- what are the expectation from this companies ?
- How can I trust you stability?