Can I called loadMethod while Ad is closed/onAdDismissed - AdMob?

I want integrated AdMob into my app. but here is an issue we manually need to reload Ad for showing. I want to try when some close/Dismiss the Ad automatically load again that I called it again onAdDissmissed method. Is this a policy violation? or Is a good programming practice or not?

Here my code oncreate method

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_my); 
    loadMethodAdMob(); 
}

load Method

public void loadMethodAdMob() {
    AdRequest adRequest = new AdRequest.Builder().build();
    InterstitialAd.load(this, AD_UNIT_ID, adRequest, new InterstitialAdLoadCallback() {
        @Override
        public void onAdLoaded(@NonNull InterstitialAd interstitialAd) {
            // will be null until an ad is loaded.
            MyActivity.this.interstitialAd = interstitialAd;
            mToast("Ad Loaded");
            interstitialAd.setFullScreenContentCallback(new FullScreenContentCallback() {
                @Override
                public void onAdDismissedFullScreenContent() {
                    MyActivity.this.interstitialAd = null;
                    mToast("The ad was dismissed.");
                    InterstitialAdMob(); // i called it here is this ok
                }
                @Override
                public void onAdShowedFullScreenContent() { 
                    mToast("The ad was shown.");
                }
            });
        } 
    });
}

button click

public void buttonClickShowAd(){
    if (interstitialAd != null) {
        interstitialAd.show(this);
    } else {
        mToast("Ad did not load");
        requestForReload();
    }
}