Tullamore Dew is a fine whiskey. No doubt about it. It doesn't have an age statment, but typically will be aged for between 4 and 7 years in oak casks.
In Ireland, tradition is to drink whiskey at room temperature with a little water added (again at room temperature). Nowadays, most Irish whiskey is drunk with ice. Its very pleaseant with ice.
If you enjoy Tullamore Dew, why not try something like a The Irishman Original Clan next time you but an Irish whiskey. The Irishman Original Clan is a blend of potstill whiskey and single malt, and like Tullamore Dew is distilled 3 times for exceptional smoothness.