But since I now both have a credit card and the expansions are only $20 for everything I was wondering if the game was still pretty active for a P2P game or if it's starting to reach the "dead" levels of many F2P MMOs out there (aka: semi-dead during non-peak hours, so many non English players that you can't talk to anyone, ect.) Is it worth possibly getting into?
This is difficult. I can't speak to what the experience might be like for a BRAND NEW player in 2011. Right now I think the game is better than it's ever been, and leveling from 1 to 90 is a lot easier than 1 to 75 was when I started in 2006. But the fact is that there are less players now than there were then, and a LOT less people that would be at the same place as you. You would benefit greatly from having a friend that can "mentor" you along the way, help you duo through some of the uglier leveling spots.
Depending on job, though, you can easily solo to about 60 and then Abyssea-alliance your way from there.
I would recommend you get into it. I think it's a great MMORPG with so much wonderful content to explore.
Your other option if you're an FF nut is to wait until FFXIV comes out of life support (hopefully for the better). It could be a totally new / awesome experience by time of PS3 launch (which I estimate as being Christmas 2011 or January 2012, based solely on gut instinct). But it's your call.
If you join the Leviathan server, plenty of 'Fan-ers on there.