Stage 1 should have high chance of recovery so don't worry too much. My mother (70+ years old) had survived a stage 3c her2+ cancer for 6+ years now. A relapse occurred last year but current treatment still able to put the cancer cells under control. There are very effective targeted therapy for her2+ breast cancer with less severe side effects than other chemotherapy.

If finance is a concern, you may get your treatment in PPUM. The doctors there work in team and are very professional. Due to the number of patients there queuing is inevitable though.

If you are not a regular, can start exercise. It can help your body to withstand the treatment and recover quickly. My mother joined Guolin Qigong but I think any low to moderate intensity exercise will work.