Is it possible to get breast cancer metastases after 15 yrs?

Unlikely but yes. Time to recurrence curves have two peaks - one at 3-5 years and a second longer tail. Er- tumors if they recur are almost all in the first peak. Er+ tumors can recur more distantly in the future. After 10 years (or sooner if er-), one must asses if it is a recurrence of the original tumor or a new second primary.
Yes. Not common, but I have seen one patient with a metastasis 25 years after surgery!