Hi Spillsy, I was diagnosed at 44 and with relatives who had also had BC I too was concerned for my sister and my nieces etc. With a fair few relatives with various cancers I went through a questionnaire with the genetics dept at Randwick, the result of which was that given how many relatives I actually have (Irish family) and their ages when diagnosed I had a less than 2% chance of mine being genetic.
You can talk to your oncologist about whether or not it's worth doing the questionnaire in your case.
Aine