I certainly don't think we should limit this board by age. I also think the OP's issue is pertinent to this board and could occur among people of any age (minus the specific HS cheerleading setting). There are other teenage ehellions whose contributions are well-received.
What I think people find jarring is the OP's odd writing style. Abbreviations such as "u" for "you" and failure to capitalize are normal if difficult to read (also, every computer or phone typing program I use capitalizes automatically at the start of a sentence - it seems like you have to go out of your way not to capitalize nowadays!). However, while there are many teenagers who speak in the stereotypical "teenspeak" the OP uses (I was one, in fact), I've never known any of them to write that way, even in conversational writing such as e-mail, instant messaging, or text. It's clear that bellacullen is a skilled writer, but it seems she's making a conscious effort to write like a stereotypical teenager speaks. Inserting "like" in random places is a verbal tic, similar to "uh," not something I would intentionally include (except for effect), KWIM?
This is not to criticize you, OP, as you seem intelligent and articulate. I definitely write conversationally rather than "properly" on ehell, but I also try as much as I can to eliminate unnecessary details (such as your long list of who called whom with a piece of gossip) and express myself clearly. My advice to get people to take you seriously and focus on your issue instead of your age is to write naturally. You can just say you're a high school student, you don't need to show it through your language.
As to your question, take the high road and refuse to participate in the gossip.