im far from the best player here, so take what i have to say with a grain of salt, but:
basically, if you're going to make a sacrifice you have to evaluate the position before and after, and ask yourself if you're going to accomplish one of the following things, preferably in this order:
1. will it lead to checkmate?
2. Can I get the sacrificed material back?
3. Do I get significant enough positional compensation to justify the loss of material?
In this case, sacrificing the knight wont accomplish anything that hxg3 can't do. it would, however, deprive you of an extremely well-placed knight on f3
The idea of positional compensation is tricky, and I wouldn't recommend it for beginning players. Its kind of like implied odds - we always think we get more than in reality. An example of a positional sacrifice is this game:
where white sacrifices the queen for two minor pieces, but also gains tremendous activity for his pieces. Spielmann went on to win the game. However, it takes an incredible amount of skill and knowledge about the game to make this kind of sacrifice, so for now I would say dont even consider it, just play solidly and work on your tactics