You can go back to China as soon as possible. There are generally no restrictions. When you hand in your homework, all you have to do is staple the paper into a booklet, burn a CD-ROM of information, and then submit it to the administrative office, then sign it and get a receipt. Generally, a receipt is to prove that you have handed in your paper, mainly to provide proof of finding a job.
Generally speaking, papers will be started from June to September, and most schools will be divided into groups, and then meetings will be held regularly. My former tutor was responsible for reporting to her once every three weeks, and I would read every part carefully. If your tutor is like this, it is estimated that you will take time off to go back to China with her.
It's ok if it can be finished ahead of time with quality guaranteed.
Generally, there are fewer papers submitted for graduation, because better schools will require libraries to keep paper copies.
You can send me a message if you have any questions.