def first_negative_index(numbers: list[int]) -> int:
    # Escribe tu solución aquí
    minus = 0
    if len(numbers) == 0:
        return -1
    else:
        for num in numbers:
            if num < 0 :
                minus = num
                break
    
        if minus == 0:
            return -1
        else:
            return numbers.index(minus)