Yes, it's informal or slang, so it's fine for spoken English and for informal writing. There's nothing grammatically wrong with it, and it has no negative connotations that I know of, except that it dates you a bit. I don't know if people your age (however old you are: your profile says "14 years old" and "in the USA") say that these days. The other thing to look out for when using slang or informal English is what the people you generally talk with say. Use their expressions, even if you're a native speaker of English, because if you use expressions that they don't, they may think you're weird (if you care).
"Huh" can mean "What?" or "Isn't it?" if the intonation is rising.