Psalm 18-partial psalm of David...
The Lord is my rock, (with the help of Mary- queen unconquered) and my fortress ( unless I call Mary Temple Indestructible or temple unassailable), and he that delivers me (unless Mary is called deliverer of all wrath), my God (with Mary as the gate of heaven, dispenser of grace), and my strength (with the Virgin most powerful), in him will I trust (with Marys help unless I pray that I put my trust and fly to her) , my shield (Mary protectress from all hurt or helper of all in danger), the horn of my salvation ( other Mary as my soul’s saving), and my refuge( with Mary as the refuge of sinners and refuge in time of danger)....
How did David know he was writing about Mary?
I don't agree with your interpretation of the psalm, therefore your question is best directed to the one who inspired the human author to write as he did. If you ask the Holy Spirit, he will guide your understanding. If you're looking for Catholic teaching about Mary, you can consult an online catechism. If you're looking to snark or insult, you'll have to find another Freeper to play along. I'm not much interested. Peace be with you.