Definitely get all the information you can. When I met with the medical oncologist, once she realised she didn't need to simplify info for me, she gave me so much detail. Specific stats of what treatment would add what percentage to recurrence and survival rates etc.
I had stage 2 grade 2 ER/PR+ HER- at 45. I opted for a mastectomy due to anxiety and 2 sentinel nodes were biopsied. Nodes were clear and tumor was the size it showed on MRI 5 weeks before surgery (35mm at largest point). My surgery choice meant no radio and my surgeon had hoped no chemo. However I wasn't expecting to be told by the med onc that 'I should consider chemo as it could help a little bit'. I was proper 'grey zone' and an ideal candidate for genomic testing. That came back as a low risk of recurrence and chemo was not recommended.
What I learnt through this process is what is probably most relevant to you. Chemo only 'sees' rapidly multiplying cells and attacks them. So hair, nails, immune - and cancer. But not all cancer. In my case, genomic testing showed it was a 'slow grower' therefore, chemo would be unlikely to find any stray cancer cells as they wouldn't be doing anything fast enough to raise chemo's attention. We have no idea how 'old' my cancer was as I had no lump and never had a mamogram before (this one was to check what turned out to be a cyst), but given it was 3.5mm of IDC spreading out from 10mm of DCIS, I'd say it had been there a while.
In your case, it sounds like yours is fast growing - so their recommendations will all be based on this. Plus you have the multipliers of young age and grade 3 too. So I'd start to mentally prepare that they will want to throw the kitchen sink at it! All the best, I found all of the decisions needed so stressful and overwhelming!