I had full ASL instruction prior to being mainstreamed. I was enrolled in an ASL program (along with written and spoken English and speech therapy - it was a 3-part program) starting when I was 1.5 years old. I was fluent (or as fluent as you can be at 5 years old 
) by the time I entered Kindergarten.
But yes, after that, no formal ASL instruction, not that I needed it since I had completed learning ASL, but for those who didn't have that opportunity, many weren't even provided that opportunity.
I'm sure my Deaf history and culture didn't really come until later, though. Post-high school. That was just a result of being mainstreamed in public schools, much like you said. Got really immersed into it in college.
