We are among those who started quite early (the little one was only 4 years old), because I believe that a child should start learning a foreign language when he is learning to speak the fastest. At first we thought it wouldn't have any effect, because the first classes the child didn't seem to pay attention and she was just looking forward to the game at the end of the class. But after a few weeks she started speaking more English than Slovak at home and she is also trying to teach English to Grandma :-)
My daughter was 5 years old when she started "going" to these classes. Previously, she went to a language school in the city, where she skipped many paid hours due to children's illnesses. That's why we like that we haven't lost a single lesson here yet, and the little one has been learning for two years. I am surprised how she is attracted to these lessons, as they play, sing, dance and the child does not even know that he is learning. My daughter is very much looking forward to every lesson.
I attend classes with this company for 2 years already so when my teenage daughter wanted to improve in English, it was an easy decision. She is quite picky and tried about 5 teachers until she decided to keep one. Now it's been a year since she started and is satisfied. She likes English and attends competitions to prove it. Even when the schools had to close during the pandemic in 2020, nothing has changed about my daughter's language learning style so having it online turned out to be very useful.