Some sage advise is offered to you by CFC_, Alec.
Consider it.
As for much of the rest you've been told?
Pick what you want -- that which makes sense to/for you -- & disregard the rest.
But above all?
Don't stop thinking, don't stop writing. Ever.
To be good, really good?
You must practice, practice, paractice & then, as another poster suggested, "edit-edit-edit."
You'll come to understand that POV perfectly well one day, & then you'll tell another young aspiring would-be writer the very same thing.
But for now?
You're well on the right track to success.
...if you stick with it.