I want to send feedback on the work of my tutor ("tutor's work" is shorter but "the work of my tutor" is also correct."

I really like using the English language to explore the world and discover new opportunities. English is the international language spoken by many people. (perfect.) I can travel to other countries and learn about other cultures. Currently I have a low level of English, but I'm trying to improve it. (lol your English is excellent) Olga is my mentor, my friend, and my critic.
Olga is a great teacher: she gives systematic training, individual approach, selects what you really need, and very often brings something new and interesting in the lessons. I am expressing gratitude to her! I plan to continue with her classes and reach with her to success.

Excellent. Very well done.

I want to send feedback on my tutor's work.

I really like using  English language to explore the world and discover new opportunities. English is an international language spoken by many people. I can travel and learn other cultures. Currently I have a low level at English, but I'm trying to improve it. Olga is my mentor, my friend and my critic.
Olga is a great teacher:systematic training, individual approach, selects what you really need, and very often brings something new and interesting in his  lessons. Expressing her gratitude! I plan to continue with her classes and reach  success.