To check your AdobeID in Adobe Digital Editions (ADE) click on Library->Authorize Computer...
You should see your email address which is your AdobeID.
If for whatever reason you authorized with the wrong email address you can deactivate the authorization and re-authorize.
Launch Digital Editions
Enter the key-combination of D (D on Mac OS)
At the dialog, confirm that you wish to de-activate the machine
Quit Digital Editions
Relaunch ADE and you will be prompted to enter your AdobeID
If this does not work you can try to delete ~/Library/Application Support/Adobe/Digital Editions/activation.dat then restart ADE and re-authorise the computer.