Writting a letter to a Japanese host family

So i am currently trying to go on exchange in Japan next year and i have to write a letter for a potential host family. I really want to write the last part of it where i thank them in Japanese and therefore wanted to know if i can write it the way i've done.

(Thank you for your hospitality)
あなたのおもてなしを本当にありがとうございました。
(My japanese is still not very good so im sorry if i make mistakes)
わたし の にほんご お まだ みじゅく なので もし まちがって いたら ごめなさい。
(I want to study more japanese and will do my best to learn it)
日本語をもっとべんきょうしたいです。私は日本語のべんきょ、がんばりますよ。
(It look foward to seeing you it means a lot to me)
あうのをとてもたのしみにしています。 私にとって大きなイベントです

Thanks a lot in advance for helping me. It's so nice of you :)

(Thank you for your hospitality)
あなたのおもてなしを本当にありがとうございました。
- This sound like they have hosted you already (in the past) and you are thanking them later for all the kindness/hospitality they have extended to you. It will be next year, right? I will rephrase it to say “Thank you for being/offering to be a host family.
I would say:　ホストファミリーをしてくださるとのこと、ありがとうございます。

(My japanese is still not very good so im sorry if i make mistakes)
わたし の にほんご お まだ みじゅく なので もし まちがって いたら ごめなさい。
- Just a few typos on this one:
わたし の にほんご は まだ みじゅく なので、もし まちがって いたら ごめんなさい。
-

(I want to study more japanese and will do my best to learn it)
日本語をもっとべんきょうしたいです。私は日本語のべんきょ、がんばりますよ。
- Just one typo, and I am omitting the よ at the end of the sentence (I am sure you’ve added it for emphasis, but this can sound somewhat overbearing.)
日本語をもっとべんきょうしたいです。私は日本語のべんきょう、がんばります。

(I look foward to seeing you it means a lot to me)
- あうのをとてもたのしみにしています。 This one is fine. Have you learned the respectful expressions yet though?
- 私にとって大きなイベントです. Why did you use the word “event” just in the Japanese?
If you want to say “it means a lot to me” “it is significant (if I can do a home stay in Japan),” you could rephrase it to say “I would be very happy if I could do home stay with you in Japan.” Do you want to give it another try?

(I am only suggesting changes as I believe that the students should be writing sentences they themselves can understand and write.)