你好！我傢家有五口個人。，包括媽媽，、爸爸，、妹妹，、弟弟，和我。我媽媽是醫生。今年我開始復複習寫中文(國字)漢字。，但是我寫漢字寫得很慢。

你好！我家有五個人，包括媽媽、爸爸、妹妹、弟弟，和我。我媽媽是醫生。今年我開始複習寫中文(國字)，但是我寫得很慢。

We don't really say  "漢字(han-zi)" when talking about Chinese or the characters. It sounds more like Japanese. I learned a little Japanese, whose word system includes "平假名(ping-jia-ming)", "片假名(pian-jia-ming)", and "漢字", but I never used "漢字" to say the characters of Chinese. I only say "國字" or "中文". "中文" is broader, and "國字" is specifically used when talking of the words. 

About me (written in Chinese (traditional characters))

你好！我家有五個人。媽媽，爸爸，妹妹，弟弟，和我。我媽媽是醫生。今年我學習中文漢字。我寫漢字很慢。

About me (written in Chinese (traditional characters))

你好！我家有五個人。媽媽、爸爸、妹妹、弟弟和我。我媽媽是醫生。我今年學習漢字，我寫漢字很慢。

Hi I think this is better!

when we want to say a series of members or things  we will use "、＂between two words in Chinese.

And between last one and last second one you can use "和＂or＂以及＂.its same!

五＂口＂人: I think "口＂ is more formal but "個＂ is more oral speaking. 

今年我：its not wrong But it sounds weird! So "我今年＂ is better!

And when we talk about "漢字＂you don't have to say "中文"because 漢字 is Chinese word so you don't have to say  that , it sounds weird too.

i hope you can understand my poor English describe!

About me (written in Chinese (traditional characters))

你好！我傢有五口人。媽媽，爸爸，妹妹，弟弟，和我。我媽媽是醫生。今年我復習中文漢字。我寫漢字很慢。

錯字修改

你好！我家有五口人。媽媽，爸爸，妹妹，弟弟，和我。我媽媽是醫生。今年我複習中文漢字。我寫漢字很慢。

文法修改

你好！我家有五口人。媽媽，爸爸，妹妹，弟弟，和我。我媽媽是醫生。今年我學習中文漢字。我寫漢字很慢。

"複習"是指曾經學習過，再重新練習。同英文的Review

"學習"是指在什麼都還不會的情況下，去吸收新的知識。

About me (written in Chinese (traditional characters))

你好！我家有五個人：爸爸、媽媽、弟弟、妹妹與我。我的媽媽是(一名)醫生/醫師。我今年開始複習中文(漢字)，(目前)寫字速度很慢。

「複習」亦可寫作「復習」。