Can I literally blunder in my first move?

Nah if that's true I'm cooked

1 g4? loses by force.

1. g4 is worst move, so yes you can make blunder in first move.

2. e4 f5 for black.

"e4 f5 for black."

• or 1 e4 b5, or 1 e4 g5, or 1 d4 g5, or 1 d4 e5...

If you want to blunder on move 1, play Chess960, Three-Check (1.e4 d5??) or other variants.

It's easier to metaphorically blunder.

@tpr said ^

1 g4? loses by force.

1.g4 is the Grob Opening and is generally considered terrible—but you actually have to win against it first. John Nunn once lost against it:

That is because of the blunder

@tpr said ^

1 g4? loses by force.

You don't know this.

@RuyLopez1000 said ^

You don't know this.

Indeed, it has not been computed that 1. g4 (or any of the other variations tpr mentioned) loses no matter how the game continues.