Setting servo speed with using push buttons

In this modification, servo speed is changed via 2 push buttons. One button increases the speed, other one decreases it.
Circuit is shown in the below :

Servo and two push buttons

CODES :

#include <Servo.h> 

const byte buttonPin[2]={2,3};

const byte servoPin = 9;

int servoSpeed = 100;

const byte minLimit = 0;

int servoPosition = 0;

boolean servoIsHigh = false;

// Create a servo "object", called servo1. Each servo object

// controls one servo (you can have a maximum of 12):

Servo servo1;

void setup(){

  Serial.begin(9600);

  servo1.attach(servoPin);

  servoPosition = servo1.read();

}

void loop(){

  

  if (!digitalRead(buttonPin[0])){

    servoSpeed = servoSpeed + 10;

    delay(20);

  }

  if(!digitalRead(buttonPin[1])){

    servoSpeed = servoSpeed - 10;

    if(servoSpeed < minLimit){

      servoSpeed = minLimit;

    }

  }

    Serial.print("Speed Servo");

    Serial.println(servoSpeed);

    Serial.print("Servo position");

    Serial.println(servoPosition);

    delay(20);

    servo1.write(servoPosition);

    if(servoPosition > 180){

      servoIsHigh=true;

    }

    if(servoPosition < 0){

      servoIsHigh=false;

    }

    if(servoIsHigh){

          servoPosition-=10;

    }else{

          servoPosition+=10;

    }

    delay(servoSpeed);

  

  

}