(I'll be honest, I had to look it up.)
The answer appears to be four.
1) During the Annunciation
2) Her visit with Elizabeth
3) The Finding in the Temple
4) The Wedding Feast at Canaan
Perhaps none are as important as those last words we have from her:
"Do whatever He tells you. " (John 2:5)
What a beautiful command that is.
If we follow it, hopefully our souls, too, can "magnify the Lord"
God Bless you on this feast day of the Assumption.