You're using too little trigger. This means you are probably using the pad or tip of your trigger finger on the trigger then at the last moment, squeezing the gun's grip.

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This is a very common complaint with new Glock owners. With practice and understanding the mechanics of proper hold and trigger discipline, you'll come around and be able to hit point of aim.

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Southern Boy thanks for the link

You're welcome. Try using a bit more of your index finger on the trigger and you might also use the isosceles stance, slight bent forward with your weak leg moved a little forward as well. Get a firm grip on the gun and a good sight picture. See if these tips don't help move your hits more to the center of the target. Another thing you might want to consider down the road is an after market set of sights. If you go this route, don't take a snap decision, but rather give it a little time and a lot of research. Think this change through.

Every time I pick up a Glock after shooting other guns , I do the same thing ! Snap caps , Glock triggers are weird until you shoot them a lot !

PS: Possible sights might be off.!