"Én szép vagyok" is correct it means "I am beautiful/nice/pretty".
"Én is szép vagyok" is also correct it means "I am beautiful, too".
"Is" means "too" (also, as well).
"Ő szép" is correct and it means "She/he is beautiful". Furthermore "Ők szépek" is the correct way to say that "They are beautiful."
Hope this helps. :)