New staging guidelines?

When I was diagnosed last September I was put, after surgical report, at IIb. I had tumor @ 1.1 and 5 nodes (two "barely" positive and three "microscopically" and grade 2). The other day my oncologist said that new staging guidelines in last few months may put me at IIIa. WTF? That is a big change. And who are "they" who change guidelines? She then said there is also a new line of thinking that says "breast tumor biology is destiny" and she says if that's true then I'm home free cause of my high estrogen receptor status and low Oncotype. But she says the truth likely lies somewhere between the two. So I ask you all...does it really matter which it is? I mean... Isn't whatever is going to happen going to happen? I hope I'm making sense.