This is a letter of thanks to Jenny

Hi Jenny,
Today is your last day in our company. I feel so upset. :( Here, I want to give you thanks for all your all help in the past 16 months.
Thinking back to the first interview, you said I couldn't leave before you. Luckily I keep my words.
I progressedive a lot in these months with your guidance. You were so kind, patient and caring to me. I am glad to have workeding with you, it's That's really been a good experience for me.
Hope you can have a good future in your next company.
Happy Mid-Autumn Festival! :)
Best wishes.

This is a letter of thanks to Jenny

Hi Jenny,
Today is your last day in our company. I feel so upset. :( Here, I want to thanks you for your all your help in the past 16 months.
Thinking back to the first interview, you said I couldn't leave before you.[space]Luckily I keep kept my words. Not sure what you are trying to say here.
I progressive progressed a lot in these months with your guidance. You are so kind, patient and caring to me. I am glad to working have worked with you.[space]That's really been a good experience for me.
Hope you can have a good future in your next company. Better to just say: I wish you well in the future
Happy Mid-Autumn Festival! :)
Best wishes.