Christians

Am I correct when I say that the Quraan says that Christians believe their Trinity to be The Father, the Son and Mother Mary?

Christians believe the Trinity to consist of God the Father, Jesus the Son and the Holy Spirit (God’s presence and power in creation).

If that is true, does it not mean that that is an actual mistake in the Quraan? How can the Quraan be the Word of God if it has mistakes?