I dont want a script so i am not requesting for something, i just want to know if you can detect if someone entered my game and never entered before or if they did enter my game before, if you want to post a script it is fine and quite helpful :)
This is only a yes or no answer.
There isn't something built in to check this in specific.
However, you could really easily use Data Persistence to accomplish this, by storing a key "has visited" (or similar) whenever a player joins (but before that checking if it's already set to see whether or not this is the first time they've played).