DFPlayer is not random?

Hello, I have a problem with my script for a miniDFplayer. I want to play a random file at the touch of a button, but unfortunately the player always plays the same songs in the same order.

here is my script

#include <SoftwareSerial.h>

#include <DFPlayerMini_Fast.h>

#define RX2

#define TX3

SoftwareSerial mySerial(RX, TX);

DFPlayerMini_Fast myDFPlayer;

int buttonPin = 4;

int lastButtonState = HIGH;

int buttonState;

int buttonCount = 0;

void setup() {

mySerial.begin(9600);

myDFPlayer.begin(mySerial);

pinMode(buttonPin, INPUT_PULLUP);

}

void loop() {

buttonState = digitalRead(buttonPin);

if (buttonState != lastButtonState) {

if (buttonState == LOW) {

buttonCount++;

int fileNumber = random(1, 10);

myDFPlayer.play(fileNumber);

}

delay(50);

}

lastButtonState = buttonState;

}