I agree with the above comment. To look up to somebody it is usual to know them personally. You can admire lots of different types of people, for example you might admire a celebrity such as a musician, sportsman or actor but it would be strange in my opinion to say you look up to these types of people. Looking up to is used for a person older than you, it might be a parent, an older sibling or cousin etc and you think of them as a role model.