Do you always need to put a comma after the word so if it is first in sentence?

You don't always need a comma after "so" when it's the first word in a sentence. It depends on the sentence structure and intended meaning. Here's a breakdown:

When you DO need a comma:

* When "so" introduces a dependent clause: The dependent clause needs a comma to separate it from the independent clause.

* Example: "So, the party ended early." (The independent clause is "the party ended early.")

* When "so" introduces a contrasting idea: The comma emphasizes the contrasting relationship.

* Example: "So, I didn't go to the party, but I stayed home and watched a movie."

When you DON'T need a comma:

* When "so" introduces an independent clause: The sentence is grammatically correct without the comma.

* Example: "So the party was fun."

* When "so" is used as an intensifier or conjunction: It's not introducing a separate clause, but rather modifying a verb or phrase.

* Example: "So I am excited about the party." (Here, "so" intensifies the verb "am")

Key takeaway: Think about the role "so" plays in your sentence. If it's introducing a clause or a contrasting idea, a comma is usually necessary. If it's intensifying or acting as a conjunction, the comma is typically unnecessary.