Google Reward Ad for admob on flutter, not showing after i click on button

Question

I want to open a RewardedaD when the user clicks on a button (Hint button), but the Rewarded Ad does not show on the first click, its loads and then stops, but the RewardedAd shows when i click the button a second time, i followed the tutorial from https://codelabs.developers.google.com/codelabs/admob-ads-in-flutter#3

I don't know what i have done wrong.

here is my code:

void _loadRewardedAd(BuildContext context) {
    //get a reward ad ready

    if (MobileAds.instance == null) {
      MobileAds.instance.initialize();
    }

    RewardedAd.load(
      adUnitId: AdHelper.rewardedAdUnitId,
      request: AdRequest(),
      rewardedAdLoadCallback: RewardedAdLoadCallback(
        onAdLoaded: (ad) {
          _rewardedAd = ad;
          _isRewardedAdReady = true;
          _isHearIconPressed = false;
          _isGetLivesPressed = false;
          _hintPressed = false;
          // isWumupsCryButtonPressed = false;
          // isWumupsCryButtonActive = false;
          setState(() {
            //done fetching the ad
          });

          createLives(currentLivesLeft);

          ScaffoldMessenger.of(context)
              .showSnackBar(SnackBar(content: Text("Ad is ready")));
        },
        onAdFailedToLoad: (err) {
          // _rewardedAd.dispose();
          print("Unable to load aD ---------------- ${err.message}");

          _isRewardedAdReady = false;
          _isGetLivesPressed = false;
          _hintPressed = false;
          _isHearIconPressed = false;
          // isWumupsCryButtonActive = false;
          // isWumupsCryButtonPressed = false;

          createLives(currentLivesLeft);

          setState(() {});

          ScaffoldMessenger.of(context).showSnackBar(SnackBar(
              content: Text("No Internet, Please Watch an Ad to get Life")));
        },
      ),
    );
  }

the code above is supposed to get the rewardAd ready, and below is my code for calling the RewardAd to be displayed.

onTap: (this._hintPressed)
    ? null
      : () {
                                           
         _loadRewardedAd(context); //get the rewarded ad ready

         _hintPressed = true;  //So i can show a CircleProgressIndicator() on the bulb Button

         setState(() {}); //rebuild to the CircleProgressIndicator() so it can show
         
         if (_isRewardedAdReady) {
              _rewardedAd!.show(         // show the reward ad
                   onUserEarnedReward:
                    (RewardedAd ad,RewardItem item) {
                          createHint(widget.questions[currentQuestionIndex].answer); //show the hint
                            showHint = true;     // so the hint can always be shown
                            _hintPressed = false;  // remove the CircleProgressIndicator();
                            setState(() {});   //rebuild so everything can be updated.
                    },
        );

          _rewardedAd!.fullScreenContentCallback = FullScreenContentCallback(onAdShowedFullScreenContent: (ad) {}, 
          onAdDismissedFullScreenContent: (ad) { // when the ad is dismissed by the user
                  _isRewardedAdReady = false;   // set the rewardedAd to false so we can call it again
                  _hintPressed = false;     // remove the circleprogressIndicator
                  _isHearIconPressed = false;    // remove the circleProgressIndicator from the heart
                  
                  setState(() {});  
                  _rewardedAd.dispose(); //dispose the rewardedAd 
         }, 
         onAdFailedToShowFullScreenContent: (ad, error) {
                   _isRewardedAdReady = false;
                   _hintPressed = false;
                   _isHearIconPressed = false;
                   _isGetLivesPressed = false;

                   setState(() {});

       });
       }
      },