Oncotype Score 23

Hi I’m 57. Had menopause a long time ago.  Diagnosed with breast cancer grade 2 level 3 (aggressive type).  Thankfully caught early, removed, clear margins, cancer gone.  Oncotype score is 23. They have offered a course of chemo as it’s near 25 but from what I see it is not necessary if under 26.  I don’t want to take chances that the cancer could have travelled somewhere in my blood but I also don’t want to damage my immune system unnecessarily and be ill with side effects for 3 months as I have a special needs child.   Not sure what to do.