I would advise beginners to use only decentralized exchanges for security reasons. There you can be sure that the exchange does not control your funds and does not have access to your personal wallet. You do not create an account on the exchange, just deposit money on a smart contract. Because trade is managed by smart contract sellers, and buyers can trade peer-to-peer, without intermediaries.
Isn't it bad for newbies to trade on decentralized? As far as I know on etherdelta every action you made has a charge. Aside from those is that newbies may accidentally buys a shitcoins that they cant reverse anymore. Since you are a newbie please read threads that talks about decentralized exchanges are not for newbie traders. That threads are almost a yearly old ones.