First command from USB not requonized. [SOLVED]

The following script should be used to check the connection to a stepper motor and determinate the maximum speed ect. true a menu.
After starting the program the first entered command doesnt work, the second creates a respond.
Any suggestion?

#include <AccelStepper.h>

// PINS
int      YAxisDIR          =  13;          // Stepper direction output
int      XAxisDIR          =  12;
int      YAxisPWM          =  11;          // Stepper steps output
int      XAxisPWM          =  10;

int      XYEnable          =   6;          // M415C Enable output

int      yStopper1         =   5;          // Y Rotor end stops
int      yStopper2         =   4;
int      xStopper1         =   3;          // X Rotor end stops
int      xStopper2         =   2;
int      index             =   0;          // Used in the commandProcessing routine

int      commLetter = 0;

// DEGREES / STEPS CONVERSION
float    stepsPerRotation  = 200;          // 200 steps per rotation (1.8 degrees per step)
int      xGearRatio        =  42;          // stepper ratio per X degree of rotation (1:42)
int      yGearRatio        =  42;          // stepper ratio per Y degree of rotation
int      xMicroSteps       =   2;          // Value of the microsteps
int      yMicroSteps       =   2;          // Posible value's are 1, 2, 4, 8 and 16
int      xOffset           =   8;          // Numer of degrees offset from 0 or 180 degree
int      yOffset           =   8;          // Numer of degrees offset from 0 or 180 degree

typedef enum {
  X_ROTOR, Y_ROTOR
}
stepperfn;

long deg2step( float degrees, stepperfn stepper );
long deg2step( float degrees, stepperfn stepper ) {
  if (stepper == X_ROTOR) return (( degrees / 1.8) * xMicroSteps * xGearRatio);
  if (stepper == Y_ROTOR) return ((-degrees / 1.8) * yMicroSteps * yGearRatio);
}

// Steppers , see AccelStepper documotation for more information
AccelStepper stepperX(1, XAxisPWM, XAxisDIR);
AccelStepper stepperY(1, YAxisPWM, YAxisDIR);
int xMotorSpeed            =   0;          // Maximum steps per second
int yMotorSpeed            =   0;          // Maximum steps per second
int xMotorAccel            =   0;          // Steps per second for acceleration
int yMotorAccel            =   0;          // Steps per second for acceleration

char     strValue[7];
char     xStrBuffer[8]     = {
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

int      newValue          =   0L;         // Holds the new value where the dish should point to
float    newXAxis          =   0L;         // Holds the new value where the dish should point to
int      command;

boolean  First    = true;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(19200);                     // Start the Serial communication
  while (!Serial);

  pinMode(yStopper1, INPUT_PULLUP );       // Initialize the switches inputs
  pinMode(yStopper2, INPUT_PULLUP );       // The internal resistors are made active
  pinMode(xStopper1, INPUT_PULLUP );
  pinMode(xStopper2, INPUT_PULLUP );
  pinMode(XYEnable , OUTPUT);              // This is the M415C enablen pin

  stepperX.setMaxSpeed(xMotorSpeed / 4);      // Set the X rotor-motor maximum speed
  stepperX.setAcceleration(xMotorAccel);    // Set the X rotor-motor acceleration speed
  stepperY.setMaxSpeed(yMotorSpeed / 4);      // Set the Y rotor-motor maximum speed
  stepperY.setAcceleration(yMotorAccel);    // Set the Y rotor-motor acceleration speed
  digitalWrite(XYEnable, HIGH);             // Enable use of M415C controllers
  Serial.println("Stappenmotor testprogramma V1");
  command = 'h';
}

void loop() {
  // put your main code here, to run repeatedly:
  if (Serial.available() || First == true) {
    readCommand(Serial.read());
    First = false;

    switch (command) {
      case ('h'):
        Serial.println("Beschikbare opdrachten:");
        Serial.println("h    - Deze lijst");
        Serial.println("s100 - Aantal pulsen per seconde");
         command = ' ';
        break;

      case ('s'):
        xMotorSpeed = atoi(strValue);
        Serial.print("Set speed to:");
        Serial.print(xMotorSpeed);
        Serial.println(" Pulsen per secende.");
        command = ' ';
        break;
    }
  }


}

void readCommand(char ch) {
  String stringBuffer = " ";

  if (ch == '\n' || ch == '\r') {
    strValue[index] = 0x00;
    stringBuffer = strValue;
    stringBuffer.toLowerCase();
    index = 0;
    command = stringBuffer[0];
    for (int i = 1; stringBuffer[i] != 0x00; i++) {
      strValue[i - 1] = stringBuffer[i];
    }
  } else {
    strValue[index] = ch;
    index ++;

  }
}

Thanks