It's not a case of being correct or incorrect mathematically, in the same way that neither "library" nor "bibliotheque" is the correct way to refer to a building full of books you can borrow. They're different combinations of letters, but they represent the same thing.

If you make judicious use of brackets, order of operations becomes irrelevant. PEMDAS is just an agreement for how to interpret equations that don't make judicious use of brackets, and so it affects how we write them down, but not the fundamentals of maths itself - and water boils at the same temperature, whether you refer to it in Fahrenheit or Celsius or Kelvin.