No One Person Knows Everything
And neither do you.
As more and more functionality gets shoved into SQL Server, or is simply tagged as ‘SQL’, then you are going to know less and less. So get used to not knowing everything.
See, the real gift you have as a DBA is not always knowing the answer, it is knowing where to go find the answer. There is going to come a time, and it will happen fairly quickly, where you will need to go and find an answer.
Think about this for a moment, and think about where you begin your search. Are you always relying on The Google, or do you have a network of peers you can turn to when you need them most?