American Saddlebreds? Disposition?

So basically, i will probably be buying an American Saddlebred as my first horse in a couple of years when im 16. I am totally mesmerized by them. Their long legs, graceful necks, and majesties heads are (in my opinion) so beautiful. I also find the sports of saddleseat and country english pleasure totally spectacular as well. Unfortunately, in terms of an ASB disposition, i have heard they are all very hot, spooky, and hard to control. I am an intermediate rider with a very good instructor, but i would also want a horse that my sister and mom could feel comfortable riding. From your experience, i wondering if you could tell me about ASB disposition. I mean i know any horse can be hot if it wants to be, but i was hoping that this wouldn't necessarily be true for all ASBs. Please help!