You have left out the details of your training. To improve 2K times one must row distances that are shorter and at a faster pace than the target 2K pace and distances longer at a slower pace. Of course, that is vague, but that is the general idea. Being a beginner, you undoubtedly have no idea where you will end up. So this training is an iterative process. As you get faster in your training, your target 2K will come down. For starters, I would base my training on what you can now do for 2K. In other words, shorter distances are faster than your current 2K pace and longer distances are slower. Of course, there is the matter of how short and how long. Obviously that affects pace. If you cannot complete workouts, you are going too fast or your workouts are too ambitious: too many reps, too long, etc. When can do a workout successfully a couple of times, decrease the time. After four months, you should have a good feel for what kind of pace you can row for 2K.
Jim Grattan, 68, 196 lb, 75 1/2". Began rowing 1/12. PBs (66+):
.5K,1:31.1,11/13;1K,3:14.1,11/12; 2K,6:40.7,4/12; 5K,17:34.0,3/12; 6K,21:18.1,11/13; 10K,36:21.7,12/12; 30m,8337,11/12; 60m,16237,11/12; HM,1:20:25.0,9/12