Honestly, I can't remember what the first things I read were, but I do have fond memories reading Goosebumps as a kid. I'm sure there were books I read well before that, but I can't remember what they were and some are nothing more than a hazy memory involving dragons and willow trees.
I actually began writing as a young age, although I didn't start taking it seriously until I was an adult. I remember writing ghost stories as a youngster, one in particularly involving an evil living hand that ran around scaring people--this was before I knew about a movie involving a similar subject. I had a lot of fun with such stories and if memory serves me that was back in 3rd or 4th grade. I kept writing, of course, and still do to this day.
The first people to read my writing would have to have been my teachers. This would have been at the same time that I was writing ghost stories and, well, it's kind of hard to hide your work if it's for an assignment.