since i red MLP wiki and all of my friends who like MLP said that.
"Unlike the other Cutie Mark Crusaders, Scootaloo's relatives (if any) have not been introduced yet. Though Rainbow Dash often acts as a surrogate sister, they are not related.[1]" ~mlp.wikia.com
because they might be adopted sisters that doesn't make them related
Who then, are Rainbow Dash's parents? Who are Scootaloo's parents? Trust me, I have gone through the series plenty of times, I never saw anything that suggested that the two are siblings, adopted or no. (Besides, what pony in a show for little kids would abandon/die on their children?)
well you've got a point.............. but i wouldn't say its for little kids my friend is almost in middle school and she likes it no matter what.
I'm not saying older people can't watch it, I'm saying that the original target demographic was young girls.
and boys if your a bronie. 
well applejacks parents died!
NOT NECESSARILY. There is no canon proof of that. They're simply gone.
You know what I like about fiction? You can choose what to accept as reality and "reality" will change along with you.
Nothing is set-in-stone.
Nothing is set-in-stone.