If you are going to be very good in any engineering field it takes a lot of work. But, since presumidely you will be working at something that you like, the hard work will not feel burdensome. Some parts of civil engineering are more demanding than others. Civil engineers can design and build large, complex structures (e.g. buildings and bridges) while other civil engineers might be involved in designing and building roads which are difficult but not as demanding as building skyscrapers. So the difficulty of being a civil engineer somewhat depends on what you want to do and what you like to do. But, the basic education of all a civil engineers is basically the same because neither you or your instructors know what you might work on once you leave school so you will receive training in all facets of civil engineering.
Hope this helps,