I must admit that I had difficulty with this psalm. It wasn't too long. It's not like Psalm 119 with lots of verses. It only has 3. It doesn't have difficult words that I had to look up their meaning. I just had difficulty understanding why verse 1 says what it says.
I do not concern myself with great matters or things too wonderful for me.
I think a person should study and learn and try to figure out great and wonderful things. But the more I thought about it, and with the phrase before "I am not proud" I'm thinking that the psalmist is thinking about when Job questioned God. God's response was something like "Who do you think you are questioning what I'm doing. It's really none of your business." In another passage God says that His ways are not like our ways and His thoughts are higher than our thoughts.
So I decided that here the psalmist is saying that he's not arrogantly questioning God about what He's doing - like he knows better than God. Instead he has calmed himself knowing that God is in control - just like a baby rests with his mother knowing she is taking care of him. "Put your hope in the LORD." v.3
So....don't use this psalm as an excuse to remain ignorant about all of the wonderful things in the world - or the universe. Study languages. Buy a telescope and learn about the stars and planets. Go scuba diving and discover wonderful things about the great barrier reef. Study great literature or botany or molecular physics.... Go see and learn and do great and wonderful things.