ain't is a slang term and not used in written English unless you are trying to write dialect. In other situations, use instead I'm not trying, or I am not trying.

"Ain't" is kind of a slang in spoken English, but is not really an actual word and is even looked at as pretty sloppy and improper. I would not use it. examples: "I ain't trying to do..." should be "I'm not trying to do..." "It ain't right what happened...." should be "It isn't right what happened..."

Just an extra note: "what everybody else doing" isn't correct, not even in slang. You'd use "what everybody else is doing", or (in speech) "what everybody else's doing".