Anyone else finding this age hard!

My 4 year old used to be such a dream. Now I cannot remember the last time I walked into a shop and she behaved herself and walked nicely and listened. The back chat is unreal, doesn’t listen and pushes every button, super testing. I really try to keep my cool but after a while the novelty wears a little thin. I do feel like things changed when she became a big sister (16 months ago), she also started preschool at a similar time. I am not sure if it’s just normal at this age but she is like a different child! Just wondered if I’m the only one feeling a little exhausted by their child’s behaviour 😩