Right now, don’t worry too much about speed. A major mistake that people make when training for CR is that they do practice questions too fast. To get Critical Reasoning questions correct, you have to see exactly what's going on in the passages and answer choices, and you likely won't learn to do so by spending a few minutes per question. At this stage of your training, you may need to spend even fifteen minutes per question, learning to see what there is to see. Here's a way to look at this process.
If you get a new job in a field in which you are not experienced, you may not be as fast as the other people working with you, but you know you have a job to do. So, what do you do? You do the job correctly, if not as quickly as those around you, and you make sure that you learn all the angles, so that you do the job well. Rushing through the job and doing it incorrectly would not make sense. Then, as you gain more experience, you learn to do the same job more quickly.
OK, so, think of Critical Reasoning questions similarly. Your job is to do what? To get through questions quickly? Not really. Your job is to get correct answers.
So first, you have to learn to get correct answers, generally at least 10 to 15 in a row consistently, and more in a row would be better. Doing so is doing your job, and if it takes you fifteen minutes per question to get correct answers consistently, then so be it. That's what it takes for you to do your job.
Then, only after you have learned to get correct answers consistently, you can work on speeding up. Get it? Working quickly but not doing your job is useless. Better to work slowly and learn to do your job well. You can be sure that with experience you will learn to speed up, and then you will still be doing your job well, i.e., getting correct answers consistently.
Feel free to reach out with further questions.
Good luck!