1. 终于,我(的)理想实现(了),我(可以)去留学(了)。
2. 新的学期开始了,我非常紧张。
3. 我计划(去)留学。
4. 尽管已经学过几个学期的中文课,但是写字的时候(我)还是(觉得)很难。
I think your Chinese is quite good, just pay attention to the use of some preposition. And by the way, if you're learning Chinese, Hanbridge Mandarin School is recommended.
You can take a online free trial class here
http://www.hanbridgemandarin.com/