You appear to be dancing around with your words. If, as Catholics claim, Mary was sinless for whatever reason then Jesus was not the only sinless human. Thats blasphemy.
It is not I who dances around with words.
Just as Mary was ASSUMED into heaven by Her Son and did not ASCEND to heaven as Jesus did of His own power as God, she did not live a sinless life because of her own grace and power, but with that granted her by Her Son.
God, as He has done throughout salvation history grants to those whom He would use, the graces they need to accomplish His will. Whomever He calls He prepares and strengthens for His purpose.