

In order to log this cache as a find, you must first find and log a cache that was hidden on the same date as your geo-birthday. What is your geo-birthday you ask? It's the exact date you created your geocaching.com account.
On your profile page is the following line:
Member since: Saturday, 29 April 2006
The rules:
1. Any previously found cache can count.
2. All types of caches qualify.
3. If the cache has since been archived, it DOES still count as long as you logged it before it was archived.
4. These must be caches listed on Geocaching.com that you have personally (physically) found and logged. (General rules, guidelines and conditions, as stated by Geocaching.com, for logging a cache find apply.)
5. Finds without the proper verification/documentation WILL be deleted.
SPECIAL RULES NOTE: If you are unable to find a qualifying cache within 150 miles of your home coordinates, then a cache that was placed within +/- 1 days of your geo-birthday can be used.
GSAK screenshot of my Geo Birthday cache find