日本語はちょっとむずかしいですね。。

むずかしい: Basically in Japanese there are two types of adjectives. There are な adjectives and い adjectives. For the most part adjectives will always end with either of these two letters. むずかしい follows the い adjective pattern, as you can tell. The い ending does not change so long as the adjective is in the present tense.

ですが vs. けど:  Correct me if I'm wrong, but I believe that in the portion that I edited you were trying to say "Japanese is hard, but fun." If this is the case, then けど is a more suitable word for the phrase. ですが is a bit more formal, and carries a more similar meaning to 'and' instead of 'but,'  although they sometimes overlap. As a general rule of thumb though, でも and けど mean 'but,' and と and ですが mean 'and.' 

Great job! And good luck with your studies!

I hope this helps!