Did you mean 4,500 hours? A bachelor's degree requires at least 4,500 hours for eligibility. One way to see if your 4 years of experience count towards the 4,500 hours is to look at the exam content outline for the 5 domains. If you have the experience based on some or most of the tasks listed in each of the 5 domains, then those experiences can be counted towards the 4,500 hours.
I strongly recommend that you read the PMP handbook and the PMP Exam Content Outline to understand PMI eligibility requirements. Below are the links:
After reading the documents, if you have any questions, feel free to post it here again.