The easiest method is probably to search the repository for files more than 5 years old. You could schedule it to run daily, and then use the Date token along with a Date Token Calculator activity as input into your search string. Then just use For Each Entry to do what you want with the documents that are found.

If you already have a document in your workflow, and you want to get the creation date... it seems you either have to enable version control and use the Retrieve Version Information activity, or you could write your own SDK script (I believe the DocumentInfo or EntryInfo objects contain CreationDate properties). Admittedly, the SDK scripts come with a bit of a learning curve...