Am I overreacting about paper usage?

Edit: thank you everyone! I'll let her do her thing :)

My almost 5 year old loves to colour. I love that she loves to colour. Sometimes she'll take a page out of a colouring book, colour a bit of it, then start a new one. The old one basically becomes recycling.

I've started asking her to colour more of the picture if she's going through a lot of them. And she asked why if she claims to be done. I told her I don't like wasting paper (true), but also they're colouring books and she's just doing her thing.

Curious to hear your thoughts.