In my opinion this question is "how do you find your university?". And I think you can answer how do you feel about your university including university itself and your university life. Your answer むずかしいですが、おもしろいです。is answering to both how is university life and what is your university like, which is good. But at the same time, as Japanese Specialist answered, it's better to say 'What is むずかしい' and 'What is おもしろい/ Why is it おもしろい'. And I am not a professional teacher, but as a native Japanese speaker who is closer to your age, saying おもしろいです sounds like "interesting". If you find your university life or class "interesting" that's fine, but just in case, when I just tell people that I "enjoy" my school life, I say たのしいです/楽しいです/tanoshiidesu instead of saying おもしろいです. For your information, おもしろい means "interesting"(because it's educational) and "funny"(funny show, funny movie, funny person, funny mistake..etc.). たのしい means enjoyable. Here are 2 examples. A) example with たのしいです。 べんきょうはむずかしいですが、まいにちたのしいです。 Direct translation by word= べんきょう(studying) は(is) むずかしいです(difficult) が(but) まいにち(everyday) たのしいです((I) enjoy, am having fun) what I'm trying to say in English= it's hard to keep up with studying but I enjoy my university life (everyday). in Kanji: 勉強は難しいですが、毎日楽しいです。 B) example with おもしろいです。 かだいはむずかしいですが、じっけんはおもしろいです。 Direct translation by word= かだい(assignment) は(is) むずかしいです(difficult) が(but) じっけん(experimentation/laboratory work) は (is) おもしろいです(interesting)。 what I'm trying to say in English= it's hard to keep up with my assignments/ there are some difficult assignments, but I find experimentation/laboratory work interesting. in Kanji: 課題は難しいですが、実験はおもしろいです。 I hope I didn't make you get confused!

You should say 'What is むずかしい' and 'What is おもしろい/ Why is it おもしろい'. example べんきょうはむずかしいですが、ともだちとはなすのはおもしろいです。 べんきょうはむずかしいですが、いろんなひとがいておもしろいです。