Make the bootable usb again. Getting stuck at 4.8% happens to me too sometimes.
but I have one question, can I turn off my pc when booting failed?
Yes. All it did was check the media, find a checksum difference and stop.
that means I can safely turn off my computer?
Indeed you can.
thank you guys for helping.
You have usb usb3-port6: over current condition. That may cause problems with other USB devices. You should figure out what is causing this (maybe a combination of devices) and correct it.
Did you expose the Fedora Installer USB key to Windows? If so, see: Why does Windows corrupt Fedora Bootable Falsh Drive