The Church does not say that Mary aids us by her own power! It is by God’s will and it is his grace—his power alone. Mary is willing to do his will.
Without God’s plan she is just like the rest of us. (Yes she is full of grace, but she would not have been without God’s plan.)
Conversely, God without Mary is not diminished. He could have saved us however he chose, and he did. He chose this way.
It is not the Church’s will that God gave Mary a unique role. It is the Church’s observation that Mary has a unique role because God willed it.
She cooperated perfectly with his plan.
We don’t ask her to pray for us only because she is Mary. We ask all of the angels and all of the saints and our friends on earth to pray for us. Because she perfectly followed God’s will and was full of grace (conceived without sin) we know her intercession to be most beneficial.
Devotion to Mary always always always leads to deeper faith in God and obedience to his will. It never separates or detracts or steals from our worship of God. If it did, the Church would have never allowed it, accepted it, observed that it was good, believed it—however you want to phrase it.
It would not be in the Church if it was against God, because God is the authority of the Church. He promised to protect us from bonehead maneuvers like that. We trust the Church because Christ promised and sent the Holy Spirit as his guarantee.
If you can’t trust the Church quite yet, trust Christ.
18 And I tell you, you are Peter, and on this rock I will build my Church, and the gates of Hades shall not prevail against it.