Hi @juliana it is an unfortunate fact that breast cancer does not discriminate in terms of age. I am older too (63) but some things are universal.Starting with the shock and disbelief you are feeling.
There is a lot of useful general info on this website and the forum.
I found keeping a journal helping d me on a number of levels , including keeping a record of all my critical dates and things like drugs , vital health statistics ( weight for example).
Alsohow I was feeling .
And one of the best pieces of advice I received was it’s ok to cry .
Also be kind to yourself.