Interesting, but that still didn't answer my question. There are also times when people went directly to Jesus for miracles, why would you choose to go through Mary rather than go directly to Jesus? I'm just trying to understand the reasoning behind this.
Do you ask people to pray for you? That is a form of intercession. You're not going directly to the source. You're asking someone else to intercede for you. There is nothing wrong with asking for prayers. St Paul did it all the time. See Romans 15:30 and 1 Timothy 2:1–4 for example.
If you had a pressing need and had the opportunity to ask the Rev. Billy Graham or some other highly regarded preacher to pray for you, would you not ask? I would think you would since James 5:16 says "The prayer of a righteous man is powerful and effective." We Catholics believe that since Mary and the saints are in heaven that their prayers joined to ours would make them more effective. The offerings of our prayers by the saints and angels can be seen in Revelation 5:8 and 8:3 -4.