I have a bit of a dog phobia, so I know I'm not best placed to make judgments about these things. So I want you to do it for me, please 
DS(5) goes round to play with a friend every week. Friends parents (lovely, responsible people) have a rescue staffie. As far as I know it's always been a good dog, not aggressive. Affectionate, I think. They've had it for about 2 years I think.
I'm scared of it because it barks. I try not to let this show. DS loves it.
I keep reading scary stories about staffies, though, and am starting to feel worried about DS going round to play with his best friend. Tell me I'm being an idiot??
TIA