Unless you live next to the West Rail (which is unlikely given the size of Tuen Mun), you will take more time than from the GC to go to Central and you will have to change lines as opposed to a straight trip on the GC or Aegan Coast minibus or the slower 962.
But Thanks to you and Bryant, the OP is now very confused I am sure
So OP better you forget Tuen Mun (district) altogether and consider the other options listed.
For reference Bryant lives in the area but work in the area and hence does not travel regularly to Central. DeletedUser has lived there a month.
Both Moving and I (who travel DAILY to central) have lived there for + 3 years. But I guess they know better of course.
The MTR website lists the trip at 50 mn which is similar to the GC (public bus) but longer than the resident bus (35mn) and that is assuming, once again you live on top of the West Rail station while in the GC you live for sure not more than 5mn walk to the bus (which ever) station.