Can you provide the Use Case for this? Is this for a billing exercise?
What you ask would almost lend itself that way.
Firstly - States
A Service Offering Instance (SOI- a VM for ease) provisioned from CLM will have states in the CMDB of Running and Decommissioned.
Running - the SOI is currently active and maintained by CLM and visible in the My Cloud Services Console (MCSC). This is also seen as Running in the MCSC.
Decommissioned - the SOI has been decommissioned and not longer active.
Secondly - Age
So the SOI will have the date that it was requested visible again in the MCSC and once decommissioned this date will also be capture in the CMDB.
However given you have stated your 'newness' with the product suite, I would firstly recommend having some training before embarking on a in-depth solution. Definitely a CLM course and then if you wish to understand the CMDB go through the Remedy Training paths...
If you start to delve into the CMDB or other areas without knowing exactly what you are doing you may cause a lot of damage.
Some reading you might want to do -
http://docs.bmc.com/docs/display/clm31 - CLM 3.1 Home Page
http://docs.bmc.com/docs/display/ars8000 - Remedy AR System 8.0 Home Page
The Reports Console using the Web source will only provide a limited list. If you create a report using AR System, you will get all the forms and join forms therein. This is where it gets complex and you need to have a good understanding of the CMDB.
I will let our specialist team know of your approach to see if it is something they can leverage.