I was trying to make an OS and started learning x86 assembly language. I learnt some basics of BIOS and 16-bit mode. Although the issue I am facing right now is that when I load the .bin file in qemu emulator, it only prints "Hello, World!". If I change the string only it does not appear on screen. Let me share code and Screenshots here. Thanks in advance.

[org 0x07c00]
string: DB "Hello, World!", 0
MOV ah, 0x0e
MOV bx, string

_start:
    MOV al, [bx]
    INC bx
    INT 0x10
    cmp al, 0
    jne _start

inp:
    MOV ah, 0x00
    INT 0x16
    MOV ah, 0x0e
    INT 0x10
    cmp al, 0x10
    jne inp

jmp $
times 510 - ($ - $$) db 0
db 0x55, 0xaa

[org 0x07c00]
string: DB "Username: ", 0
MOV ah, 0x0e
MOV bx, string

_start:
    MOV al, [bx]
    INC bx
    INT 0x10
    cmp al, 0
    jne _start

inp:
    MOV ah, 0x00
    INT 0x16
    MOV ah, 0x0e
    INT 0x10
    cmp al, 0x10
    jne inp

jmp $
times 510 - ($ - $$) db 0
db 0x55, 0xaa

I tried figuring out why this happens but I could not find any resource so, I thought I should share my problem here.