“Just thinking about how enormous it all is... it blows my mind!”
You and a friend get into a conversation about outer space. You start to talk about the size of the universe and how many stars are in it, and you feel amazed by it. You comment on your feeling.
Just thinking about how enormous it all is... it blows my mind!
"Enormous" means "very, very, big". Here are some things that you can describe as "enormous":
an enormous amount of money
an enormous explosion
an enormous responsibility
When something is amazing and unbelievable, you can say that "it blows your mind":
Whenever I think about how many people live there, it blows my mind.
It blows my mind how talented Katie is at such a young age.
Sometimes people use this phrase to talk about something that's surprising in a negative way:
It blows my mind how some people can just lie right to your face.
You can also use this expression in the past tense:
A: How was the exhibit?
B: Oh, it absolutely blew my mind!