Question to Catholics

I really am interested in understanding why Catholics believe what they believe. If you have read the bible, you know that Mary isn't mentioned except in the gospels and Revelation. I don't understand why some Catholics think of her as divine. From what I read in Scripture, she was a 100% human. The bible says she was highly favored. In Christ, I am highly favored too! I believe the Son of God was given to her to carry in her womb even though she was 100% human and needing a Savior to save her from her sins. Consider that the Holy Spirit lives in the 100% human believer who struggles with sin. I want unity with Catholics so I desire to understand why Catholics cling to non-Scriptural doctrine. One Catholic friend told me that Jesus is more likely to listen to Mary than to her so she prays to Mary. This is scary and keeps people from a thriving relationship with God Almighty through Jesus Christ alone.