Does talking to the mother of the young man who wishes to propose to me after his commitment indicate a lack of submission of my affairs to God and a choice for myself, especially since I desire to rely on God and leave all my life choices to Him?

You did well by discontinuing the conversation with the foreign young man, as it is impermissible in Islamic law except out of necessity. If the young man is religious and of good character and you wish to wait for him, there is no harm in that, for a Muslim chooses for himself, as the Prophet, peace and blessings be upon him, said: "Choose carefully for your progeny, marry those who are compatible, and marry them off." This is a matter of taking the necessary means, and the affair is entrusted to Allah through Istikhara (prayer for guidance). A girl should hasten to marry a righteous man if one is found, and not wait for another, especially in these times of abundant tribulations.