Hepatitis shot...

I started a new job and they're offering to pay for the round of vaccines because I could be exposed to it in my line of work (residential aide) but I guess I had 2 rounds of it one in 2004 and 2005 and I don't really know much about it. I'm kind of iffy about vaccines after reading things so I'm scared and not sure what to do. My doctors office said the best thing to do would have my blood drawn to check for immunity...does any of this sound like a good idea? Like I said I don't personally know much about vaccines..I've always had them as a kid and I guess I'm fine lol but I've been reading about horror stories.