In a word, an account executive is a salesperson. Their day-to-day roles include finding new clients, serving existing customers and nailing the sale deal on the head. Essentially, it's safe to say that your communication skills have to be off the chart. Especially since most account executives work on commission.
In general, you'll probably want to secure a bachelor's degree before pursing this career. Even after you graduate, you'll probably have some more to learn. But no worries because your employer will probably supply that.