For Christmas I got a Billy Joel album called Cold Spring Harbor and I'm curious if that was Billy Joel's first ever album? It came out in 1971 and had the hits She's Got A Way and Everybody Loves You Now. I didn't even know this album existed because I always thought Piano Man was Billy's debut album

Yes, Cold Spring Harbor was Billy Joel's debut studio album. Piano Man was his second studio album.

Oh, so the Billy Joel album I got was his first album? Was Cold Spring Harbor a huge seller when it first came out or was it a slow starter at first?

It was a slow starter.