Does doing light cardio on rest days negate the rest day?

Okay, so I recently started working out and trying to be better. I have been consistently going to the gym for about two months. My schedule looks like one day for one group ( chest and arms for example), next day is a different group ( legs and back), and then on the third day, I’ll do some cardio, usually treadmill at 15 incline at 3 mph for between 45-60 minutes. It’s not intense cardio, but it gives me some activity. Should I just take a rest day instead or is this cardio okay for the most part? As a beginner, I’ve heard about the need for a rest day, but I don’t feel this cardio is too intrusive to work against me.

Thank you in advance for your feedback.