Devi,
PMI has clear requirements that you must fulfill. These are outlined in the PMP Handbook
www.pm-prepcast.com/pmphb
on page 6. If you have a bachelors degree, then they say that you need the following:
Minimum three years/36 months unique non-overlapping professional project management experience during which at least 4,500 hours were spent LEADING AND DIRECTING the project.
They also say that:
Leading and directing the project as identified with the tasks, knowledge, and skills specific in the Project Management Professional Examination Content Outline
So if you have a bachelors and also 4,500 hours of leading and directing the project, then you are OK. But if your hours are mostly as a "project contributor" then you do not qualify for the PMP.
Here is how you can determine if you qualify. Please open the PMP content outline
www.pm-prepcast.com/pmpoutline
and read all the tasks starting on page 5. If you can honestly say "Yes -- I was responsible to lead and manage these tasks" then you are OK.