I no longer want to continue studying but I don't have the courage to say that to the Witnesses.
As another comment suggested, ask your "teacher" to show you the video about stopping unproductive studies. Then ask them if THEY would do that to someone just because the person was not "progressing". Then when they say "Yes", quit the meetings, start not being home when they show up, and tell them when they ask what is going on that you have no intention of ever getting baptized.
The only studies they consider to be progressive are the ones who they believe will become baptized, and a feather in their WT hat to brag about, "I brought so-and-so into Da Troof!"