I am of the mind that it is beneficial to join a new-player-friendly corp fairly soon. I sure learned a lot from my first corp.
Importantly, however, do some research on corps…and probably best to avoid any corp that spam-mails you.
A couple of the larger more training-oriented corps are Brave Newbies (currently involved in a pretty big war) and Karmafleet (involved in the same war but part of the other side from the first lot mentioned…and their recruitment might be closed at the moment due to war, not sure). EvE University used to be fairly well recommended for newer players but I heard they weren’t what they used to be but not entirely sure about that. There is a large alliance called SICO that personally I would avoid as they kind of have a reputation of being more interested in gaining numbers on their membership than other things.
Don’t be afraid to leave a corp if you think that would be best for you. Better to have a short/otherwise odd-looking entry on your EvE employment record than learn nothing/wrong things/be exploited.
good luck!
Maybe check this out: