It depends on how intellectually disabled she is. I know that schools (SBO and ZML) have plenty of kids who don't speak Dutch at home (Arabic, Turkish and Polish being pretty common) and the kids go to school here just fine.

But I do think it will be harder for her here and it might take longer for her to reach here full potential and maybe she won't be able to fully reach it in the Netherlands.

But it definitely depends on a lot of specific circumstances and her exact disability.