Not sure if that size is normal, it does seem kind of large. In the Server Tasks section of ePO, (Menu->Automation->Server Tasks) there are some predefined tasks for purging old entries from the database that you could enable. When configuring the task, on the Actions tab, you can add multiple actions. Look for the ones that start with "Purge". If you have been using ePO for a long time and it has never been purged, you may want to start with "Purge records older than" a number of years, then gradually decrease it after sucessful completions.
Here are some KB articles that may help:
Note that after purging old items, the database file size won't be smaller, it will just have a lot of unused space in it. It appears that (based on the two articles I linked to) McAfee doesn't recommend having SQL Server shrink the databases. My guess it that a database backup (created by SQL Server) will be much smaller after the purge, but I'm not sure.