If I’m actually reading with the goal of thorough understanding then it will take as long as reading it aloud or longer. I can still skim through the text faster, but I will understand less of it.
The Wikipedia article on subvocalization has a section on speed reading. It seems that subvocalizing can in fact limit the reading speed.
Is it even possible to not care at this age though? At this point school and interacting with your peers is a vast majority of your life. I don’t think I have ever seen a kid being bullied every day at school and not caring. How can you not care if you’re scared?
I guess it is possible as you get older, more mature and closer to adulthood. But for a kid in a primary or middle school? Kinda hard to imagine for me.