Therefore a person is in heaven because they chose to be there.
True!
They accept the free gift of salvation which is offered by grace.
'choice' is not a work since it is faith that saves us and we choose to believe or not. (Jn.3:36, Rom.4:4-5)
Just like a Christian has to 'choose' to yield in his Christian walk (Rom.6), but we still walk by faith (2Cor.5:7).
So if you are not choosing to 'yield' to God, then you are choosing not to yield to God and reject His grace and thus, you grieve/quench the Holy Spirit (Eph.4 1Thess.5)
The 'choice' that God has give us is to believe or not. It is that faith that pleases God. (Heb.11:6)