Statistically they're basically the same with effective treatment between lumpectomy with radio and mastectomy. And you fortunately have a smaller cancer with lower grade.
Having said that I chose mastectomy. I had a small cancer that was aggressive. Mine wasn't visible on a mammogram 5 weeks before and even ultrasound was challenging. I was just lucky it was near breast surface and nipple so I found it. My surgeon informed me of my breast density and due to family history (1 sister, 1 niece and 3 Aunts) the decision for me was bilateral mastectomy and reconstruction. My nipple couldn't be saved so a lumpectomy didn't seem a brilliant option. The surgery will reduce local recurrence or a new primary, but not my risk of metastatic disease...which is unknown of course.
Many women have little issues with radiotherapy. It often depends on location.
Reconstructive surgery does take time and has risks so if you choose that option you should ask lots of questions.
No answer is right or wrong. Only you can choose. Take care. Kath x