Password doesn’t work on VirtualBox and Grub is too fast

I just installed ubuntu via VirtualBox and it worked fine until I had to log in. I am sure that my password is correct but it won’t let me access my account. When I enter my password it says I’m sorry but it didn’t work. Please try again. When I try to log into grub it only shows up for like 1 frame so I can’t do it and I can’t modify the file to make it longer because my password doesn’t work. It is Ubuntu 19.04.