Would I use a comma?

[Unregistered]

Hello! I have wondered about this for a while, but have never found an answer to my question, mainly because I never asked for an answer to my question. Actually, I think I may already know the correct answer to my question, but I figured I might as well ask anyway. In the sentence, "First of all, my name is Amanda, but people call me Mandy." Would there be a comma between "all" and "my", or should that comma be deleted? I ask this because I know that introductory words are followed by a comma, however most people do not use the commas with introductory words, and it makes me wonder if the comma is actually necessary. Thank you in advance!

[MrPedantic]

Hello Unreg,

The initial phrase "First of all" acts adverbially on the whole sentence. It is the equivalent of putting a "1" in front of it:

1. My name is Amanda, but people call me Mandy.

It is therefore quite helpful to the reader if a comma follows it, to mark it off.

(In spoken English, you would pause after "all", with a distinctive intonation: this serves the same purpose as the comma in written English.)

Best wishes,

MrP