Go to the Store and then select "my apps". Swipe to "History" and scroll down to the bottom to reveal the apps you have which were last updated the longest time ago.
Here are mine:
App Social - oldest
TuneIn Radio
6snap
Youtube HD
Currency Converter
Periodic Table Pro
Mathematicus
HERE City Lens
Flixster
ESPNF1
On This Day...
T-Translator
Here are mine:
App Social - oldest
TuneIn Radio
6snap
Youtube HD
Currency Converter
Periodic Table Pro
Mathematicus
HERE City Lens
Flixster
ESPNF1
On This Day...
T-Translator