A bit more information would be good. What EV version, how exactly is your policy defined etc.
To briefly explain:
If you use quota based archiving, EV will archive WHAT IS NECESSARY, to get below the targetquota. This means NEW items will also be archived if necessary. You might need to tweak a little (like 'never archive items older then 2 weeks', but be sure to get the result you want.
It is EV 11.0.0 and Exchange 2013. In quota bases policy there is no override age based settings.
At my end it is archiving new emails and old emails , emails of middle range not getting archived also , attachments and higher size emails are skipped.
If you did not manually archive items, post a screenshot of what manideep told you. So we can help.
Archiving is possible through:
manual archiving (user)
automatically archiving (policy driven)
Server driven (archive latest X items)
Migrations into the archive (for example PST)