If you are going to apply to a university, you will surely need to use your own wishes. The university is trying to get a feeling about who you are as a person. Only you can give answers that will do you any good on an application.
For me personally, there are many types of wishes I might make. I suppose that the most obvious at this point in my life has to do with my children. I hope, more than anything, that they will be able to grow up healthy and in a good situation in their lives (decent jobs, happy relationships). That's the first thing I would wish for.
If I were going to wish for something for myself, I would wish to be able to control my weight more easily. It has always been a struggle for me and I think that if I could control it more easily my health would improve in the long term without so much effort on my part.
Then, of course, I might wish for something that would help the whole world. I think I might wish for better understanding between people of various religions. I think that this could go a long way towards reducing the level of conflict in our world today.