I think what you're going to say is good. Be open about it. Lead the conversation.
Just have the mindset that nothing is lost yet. Even IF she tells you the worst things, you still keep this mindset. Like Juan said, girls think emotionally and she might be saying something different in 5 days. With 1 year of relationship there will be a solid amount of attachment she has for you.

If she tells you to just be friends, tell her that's not what you want right now and you know that's not what she wants either. You can say you respect her decision but for you, friendships never worked afterwards.

So even if the outcome is negative today, still nothing is lost. That's the mindset you need to have:

1. She loves you and you know it
2. You are emotionally strong while you acknowledge your f#ck up
3. You are a good catch
4. You can walk away and know nothing is lost

Feel free to add stuff to that mindset list if it's positive.. And read this all over again and again before you go there. You really have to believe in it. Probably set aside half an hour and focus on your mindset.

DON'T MAKE IT AN ALL-OR-NOTHING DAY, just see this day as a little step to get her back.
But you really do have to walk away before you find yourself begging for anything