Trigger model event for only one time

Hi everyone, I wanted to make a observer that handles my events. Everything ok but there's a little problem that confused me. My problem is 'created' event. I'm storing lots of 'Date' model in one time on my controller and my idea is the when all Dates saved correctly, then send an email to X person releated with 'Date'.

here is my code; // On creating; change date format

public function creating(Date $date)
    {
        /*$dates = [];
        foreach (request()->tarihler as $k => $tarih)
            $dates[] = Carbon::createFromFormat('d/m/Y', $tarih)->format('Y-m-d');


        request()->tarihler = [];
        request()->merge(['tarihler' => $dates]);*/
    }

// Send email

public function created(Date $date)
    {
        //dd(request()->all());
        $user = $date->user()->first();
        $student = $date->student()->first();
        $teacher = $date->teacher()->first();


        // currentPerm. returning 'normal' it's working good
        if (CustomFunctions::instance()->currentPermission() != "normal")
        {
            CustomFunctions::mailer('teacher.mail.context', $teacher->email, 'ILKSMS', [
                "params" => [
                    "name" => $teacher->name,
                    "email" => $teacher->email,
                    "phone" => $teacher->phone_number,
                    "mesaj" => "blabla."
                ]
            ]);
        }
  }

When I'm creating hundreds of Date in same time;

public fun. store(...)
 foreach ($request->tarihler as $tarih){
            $yeniTarih = Carbon::createFromFormat('d/m/Y', $tarih)->format('Y-m-d');

            foreach ($request->randevular as $randevuSaati){

                $date = Date::where('teacher_id',$request->teacher_id)
                    ->where('date',$yeniTarih)
                    ->where("time",$randevuSaati.":00")
                    ->count();

                if($date < 1){
                    Date::create([
                        'teacher_id' => $request['teacher_id'],
                        'school_detail_id' => $this->funcs->getSchoolDetailId(),
                        'date'=>$yeniTarih,
                        'time'=>$randevuSaati.":00",
                    ]);
                }
            }
        }
}

İt's sending hundres of mail because it's triggering Model has been saved and it has been saved hundreds time. Just send one time e-mail when it's completed insert all data