Mary’s Knowledge of Her Immaculate Conception

There is no Church tradition that would answer either way. The fact that Luke 1:29 shows Mary was confused by the angel’s greeting that she was “full of grace” would seem to indicate that she did not know or fully understand that she was immaculately conceived. The Immaculate Conception also refers to Mary’s sinlessness throughout her entire life. There’s no reason to think Mary presumed she would never fall into any sin, no matter how small.

However, she probably was aware that she was different from other people in that she did not fall into sins that others commonly fall into, but she also would have been humble enough not to presume.