For some reasons, you feel like that you are not competent enough in English whereas the skills are relatively required when you are about to get in a professional field. The problem is that you feel less success in the following English class and wonder what makes you be in this way. After some consideration, your introvert personality tends to make you uncomfortable to learn English in the class. When you gather with a number of people, you feel that you do not feel comfortable anymore. In this case, you have to find some alternatives that you can choose as you plan for taking b1 test booking.
In fact, it is possible for you to consider hiring an English private teacher. Moreover, if you think that you have no good understanding of fundamental English, it is much better for you to study with a private English teacher. In private class, as an introvert, you are going to feel much more comfortable to learn any material. As a result, you are going to feel that your private English class feels quite effective to develop your understanding of Basic English. It is quite crucial to have such proper understanding in Basic English.
When you have a good understanding of Basic English, it is much easier for you to learn the upper levels such as intermediate and advanced classes. With this urgency, it is much better for you to start finding the most suitable option of private English teacher as there a number of options of course that you have to choose.
However, as a consequence, you are required to pay for relatively more amount of money for professional private service. For the effective class, it is such a fair trade to take as long as you feel satisfied with the service. It is good that you have some friends with some good recommendations.