Q: Want to upgrade.  Is my computer too old?

Unfortunately that Mac is incapable of running El Capitan. It requires a Late 2008 or later MacBook:

• MacBook (Early 2015)
• MacBook (Late 2008 Aluminum, or Early 2009 or newer)
• MacBook Pro (Mid/Late 2007 or newer)
• MacBook Air (Late 2008 or newer)
• Mac mini (Early 2009 or newer)
• iMac (Mid 2007 or newer)
• Mac Pro (Early 2008 or newer)
• Xserve (Early 2009)

http://www.apple.com/osx/how-to-upgrade/#hardware-requirements

The latest version you'll be able to run is Lion: http://store.apple.com/us/product/D6106Z/A/os-x-lion.

Your options are described in the following:

Upgrading to El Capitan

 

You can upgrade to El Capitan from Lion or directly from Snow Leopard. El Capitan can be downloaded from the Mac App Store for FREE. To upgrade to El Capitan you must have Snow Leopard 10.6.8 or Lion installed. Download El Capitan from the App Store. Sign in using your Apple ID. El Capitan is free. The file is quite large, over 5 GBs, so allow some time to download. It would be preferable to use Ethernet because it is nearly four times faster than wireless.

 

      Macs that can be upgraded to OS X El Capitan

 

         1. iMac (Mid 2007 or newer) - Model Identifier 7,1 or later

         2. MacBook (Late 2008 Aluminum, or Early 2009 or newer) - Model Identifier 5,1 or later

         3. MacBook Pro (Mid/Late 2007 or newer) - Model Identifier 3,1 or later

         4. MacBook Air (Late 2008 or newer) - Model Identifier 2,1 or later

         5. Mac mini (Early 2009 or newer) - Model Identifier 3,1 or later

         6. Mac Pro (Early 2008 or newer) - Model Identifier 3,1 or later

         7. Xserve (Early 2009) - Model Identifier 3,1 or later

 

To find the model identifier open System Profiler in the Utilities folder. It's displayed in the panel on the right.

 

     Are my applications compatible?

 

         See App Compatibility Table - RoaringApps

Upgrading to Lion

 

If your computer does not meet the requirements to install Mavericks, it may still meet the requirements to install Lion. You can purchase Lion at the Online Apple Store. The cost is $19.99 (as it was before) plus tax.  It's a download. You will get an email containing a redemption code that you then use at the Mac App Store to download Lion. Save a copy of that installer to your Downloads folder because the installer deletes itself at the end of the installation.

 

     Lion System Requirements

 

       1. Mac computer with an Intel Core 2 Duo, Core i3, Core i5, Core i7,

           or Xeon processor

       2. 2GB of memory

       3. OS X v10.6.6 or later (v10.6.8 recommended)

       4. 7GB of available space

       5. Some features require an Apple ID; terms apply.

Hi Holly, unfortunately you cannot upgrade to El CAp. See the system requirements. You probably could upgrade to Lion.

OS X El Capitan - Technical Specifications

• MacBook (Late 2008 Aluminum, or Early 2009 or newer)

A lot that is compatible with 10.6.8 is not with 10.7 or later, read this tip first:

Upgrading to 10.7 and above, don't forget Rosetta!