To add to Sergio's response, if you have taken courses prior to getting a PMI credential, you cannot retroactively claim those PDUs once you earn the credential. However, those hours may be eligible towards the prerequisites for the credential application.
"Marta was watching the football game with me when she said, 'You know, most of these sports are based on the idea of one group protecting its territory from invasion by another group.' 'Yeah,' I said, trying not to laugh. Girls are funny."