I think the better question is really, when you should join a corp and when you should wait. Again, everyone's experience is different but I suggest you wait to join any corporation until after you've completed most if not all of the tutorial missions. There are Mining Corps, PvP Corps, PvE corps, etc. And you probably don't know what you want to do, or who you want to be until after you've played the game for a while.
You can always leave a corporation and find another one, so don't be afraid of making a life long decision that you can never change, but that doesn't mean go and try and join up with the first corp you come across. A common method of recruiting ( and trapping ) is Cargo Containers. You may have noticed by now depending on what system you're in a Cargo container or maybe twenty of them, floating around with a name of a corporation saying that they are recruiting. Some of these are legit, some of them are just trying to get you to go into lowsec space so they can blast you and pod you, or to give them money, or something else evil that you don't want to find out about.
Take your time, do your research before choosing your corp. Look them up online, read their profiles, try to do some digging as much as possible. Don't give them anything you don't have to, and don't risk anything you aren't willing to lose. Most corporations have a tax, and that's normal. Don't be afraid of the tax unless it's really high. I still don't know what constitutes really high, but I was personally comfortable paying 5% tax when I joined my corp. You may be comfortable with more, but be careful.
Unless you're joining a Lowsec corporation on purpose, don't trust them if they ask you to follow them to a lowsec system. You're just getting set up to get blasted.
Carebears.... took me a bit to figure out the term but I finally figured out what it means. It's a derogatory term for people that are afraid to take risks, live only in highsec, and never do anything illegal. My advise to you is to play the game however you want to, BUT the more you risk, the more you could gain. There is definitely more ISK to be made by taking chances, and if you made a mistake and go BOOM, then pick yourself up, dust yourself off, and learn from your mistake.
I've been podded 5-10 times already in my 3 weeks of play, and I don't regret any of them. Once again, if you can't afford to lose it, don't buy it/fly it.