How often do you practice? Do you have a shodan or senior Kyu?
First, ask the instructor. Most likely there is something you are doing incorrectly especially if you are just learning these techniques.
Aikido techniques are meant to be sensitive to the specific conditions of an attack. However, since it is often too difficult for instructors (due to time of classes) to cover all the possible condition-dependent variations for techniques, some students will adopt a general type of attack and learn to respond to that. You will see later as you advance and become better at muscle memory and become more familiar with these techniques you will see that correct transitioning will come with correct practice and training on this technique.