I didn't.
I've just been diagnosed with breast cancer and have had my first mammogram at the age of 46. I have been told that this cancer has been growing for years and that a mammogram would have picked it up long ago.
I have also learned that in the UK you can go and ask for a mammogram (I think annually) if you are over 40 and they will send you for one but they don't normally suggest it to you as it costs money to them.
I am now going to have to have a mastectomy. Don't be like me - go and have a mammogram now.