Dude, the game is so weird now. I'm not sure if there will ever be a good time to get into it. New people shouldn't be playing it. No one should probably be playing it.
 
Also there are going to be very few Mac newbies. Most have been playing off a Windows partition for years. This assumption that everyone with earbuds is an easy target is going to be put to bed very, very quickly.

ehh games ok 
css is better

If you enjoy the free-to-play this weekend definitely buy it. It has one of the best online communities of any game, it's constantly being updated with new content for free. I bought it at release (October 07) and still put in 30 or more hours a week. But even an new player can jump in and help his team, just don't pay attention to your K/D or anything; it's absolutely worthless, doing objectives and taking out high value targets such as Medics combos or Snipers is what will win the game.
Luckily it's free this weekend though so you can get a real feel for the game before you decide to buy it or not. Some advice I have for you is not to just play on 32 player instant spawn PL and CTF games, play some 8v8 on Capture Point maps.