SICILIAN DEFENSE!!!

"Is Sicilian defense one of the best?" ++ Yes, 1 e4 c5 is considered second best after 1 e4 e5. However, it allows to play for a win with black, but at greater risk of losing.
"I just started really getting into chess a couple of weeks ago and mainly use it."
++ It is a good defense, but hard to play correctly. A small slip and you lose.
"I also see that a lot of great players tend to use it" ++ A top grandmaster who wants to win a tournament has to win games with black against lesser opponents.