Well,their first song i heard was Kashmir,on a radio station.But i didnt knew it was from Led (i didnt even knew the name of the song,or that Led existed).
Before that i remember hearing a wierd remix of D'yer Mak'er,but it wasnt the original so it doesnt count.
After like 2 years or so(16 year old), i already had heard a lot about them,but didnt got interested.Then i was reading an article about the greatest solos ever, and read about Stairway to Heaven.I've saw this one a lot of times on Youtube related videos,so i decided to go and hear it.
The raw awesomeness of Stairway was too superior for my hearing, so after listening for it about like 10 times, i finally recognized the genius' work,and decided i was going to listen to them more and more.
And i still addicted to Led to this very day (it all started like 6 months ago,so i still a newbie).