But, "proof" of God's existence in this way would eliminate the need for faith. Conversely, you also cannot prove that God does not exist, making it a faith, of a sort, in both directions.
Truly, faith is a choice: you choose if you are going to have it (or try to have it), or not.
And thus not having faith is also a choice -- it's an implicit, and sometimes explicit, rejection of faith; and, thus, God.
So I wouldn't hold my breath waiting for that message from your Ma, as awesome as she sounds; if she is wrong, and there is no heaven, then you will never receive that message; and, if she is right, as I deeply and humbly believe, you will also never receive the message because that would eliminate the need for you to make a decision, personally, to have faith or not.