Mojave boot disk not installing

Hi,

I have a macbook pro running El Capitan that I want to upgrade to Mojave. When I used the installer, it did not work, so I created a boot usb using Diskmaker X. I booted from the disk, and used the Mojave install utility. At about 75% complete, the computer reboots to the boot usb. Thinking the install was done, I changed the startup disk back to my hd, which booted back to El Capitan. I tried the boot usb again, but it still booted to the macOS Utilities screen, and when I changed the startup disk, back to El Capitan. Please help me figure out how to install Mojave. I do not want to use another method besides the boot disk because installers never work for my mbp, and I do not want to waste time trying to fix that.

Thanks in advance,

pie05