Dear Jane,
I am so glad to receive your letter.
As for the problem you mentioned in your letter, I think it will be a good idea that you have a talk with your mother.
In your talk, you should tell your mother that you are very appreciated with her care first. Then, you may tell her that you are not a baby who is always in the need of much care and worries. You have already grown up and you can take care of yourself. But please remember, the reason your mother does this is only because she loves you so much.
Wish you have a good talk with your mom.
Best regards
Yours Sincerely
Li Mei