Any father with a child old enough to communicate has said something along the lines of, “If I find out later that you lied it will be worse than if you just tell me the truth.” Kids lie. People lie. In fact, as someone who often talks about spiritual things with people, this is one sin people will almost universally admit to, with some justification of course.
As a father understanding why children lie to you is important. It reminds me of a skit from comedian Louis C.K. (Disclaimer: This embedded video is clean but be careful listening to him in other videos if you try to avoid vulgarities.)