What others have said about the census is all correct. The census can be very helpful but it shouldn't be taken as absolute regarding the details. I've documented a number where male/female designation was wrong (I'm guessing the enumerator just asked for names and essentially guessed if they were male or female). My great grandfather appears on one census twice. That's because he got a job on the railroad and moved the family to his new station, then returned to their original location to settle things. It turns out the census was enumerated in the new place two months before it was in the old place. So, he was counted in his new home place with the family but also, two months later, at the old home place.
Relationships can often be incorrect. Widowed vs divorced is a common error. Divorce (or just abandonment) was considered by many to be shameful so divorced (or abandoned) women often said they were widows, thus saving face.
Many facts are often different on different censuses. Names, birth years, places of birth, relationships; these often don't agree between censuses. Thus, one must use the census carefully and try and find other sources. As one who volunteers at an historic cemetery, I can also say that what is written in stone is not always true either. So, don't just accept a photo of a stone inscription as correct.
An old rule of thumb is that one should not consider anything as true unless there's at least three sources that all agree. I could argue technicalities but will just say it's a good principle to follow: don't just accept one source - even legal ones such as death certificates - and try to verify with other sources.