I recently made a tweet towards the administrative staff at my high school that some people may consider distasteful or offensive. A couple people messaged me about the tweet out of concern that I might get into trouble with administration for my tweet, but I am not sure if this is true. I am no expert on law, but I would argue that I am using my freedom of speech. Am I in any danger from my school administrators or any lawful danger by keeping this tweet up?
There is no country in the world that has absolute freedom of speech. There are many that have extreme limits on it.
The country with the greatest freedom is probably the United States of America but even there there are limits.
For example, it is illegal to defame someone. That is, make a factual statement about a person or organization that is not true and that could damage their reputation.
For your case, as a student of the school you are subject to the rules of the school. If your statement breaks those rules you can be sanctioned. If the school is public, it would generally be as restricted as the government is in limiting free speech but, as stated above, such restrictions depend on where you are.