Agreed with everyone else that “it depends”. If you are talking about “very low” scores in the 70’s that’s so different from very low in the 20-30’s. Yes, your ssat score means something, but there are plenty of kids who score a bit below their actual academic ability.
If you come from a really rigorous school you might be fine. The problem is that lots of people think their schools are rigorous when they just are not.
Also, are you okay being in the bottom half of your boarding school class? Again ssat score doesn’t predict that but it is one possible indication.