@alternativenation
Do you remember the first album you bought with your own money?
For me it was Even in the Quietest Moment by #Supertramp
I had asked my older sister for advice, and while we didn't really have the same taste in music I wasn't disappointed.
Edit: Uhm, not sure Supertramp counts as alternative though...
Mine was Pisces Iscariot by Smashing Pumpkins. I'm not sure why I chose that particular album as it's a collection of demos and b-sides. I think I knew I was interested in the Smashing Pumpkins, but wasn't sure where to start, haha.