Informal essay

Hi, everyone, nice to meet you!
Firstly, I will introduce myself, my name is Kiki, I’m 22 years old. I want to improve my English and make friends with you through (the) italki. I know that my grammar includes mistakes (exists the mistake,) but failure is the mother of success, I believe that I can speak English fluently (English) in the future. You can contact me if you want a language exchange, (to exchange the language,) I will teach you (to learn) mandarin.
Look forward to hearing from you!

Good start. Not too many grammar errors. Well written.