You can make it so it only works in a specific area. Just use other variable for that.
It could be:
Event 1: start tracking steps variable (inside the control variables command, the last option)
Event 2: Save current steps variable (new variable = steps variable).
Event 3: when you want to count again, you have to set the steps variable to zero. This way it start from where it was last saved.
Keep in mind that RMXP already starts counting steps as soon as the game starts (in a clean XP project, essentials is maybe different around it) so you will have to reset the steps variable to zero before you start counting. You probably will need a variable as an parallel process in a common event, where it adds 1 whatever the player takes 1 step.
If you want to have it in multiple places, you have to keep in mind the Events 2 and 3.
This is just basic RMXP. I suggest that you toy around with, at least: Control Variables, showing variable in a text command, Conditional Branchs, Labels and Loops. Just learning how to use those will greatly help you in the future.