I train at a martial arts gym. I go there straight from work so am always a bit early for class, so I usually get changed and go on the mats and stretch/warm up. The kids class is still running when I get there, noticed the last couple times I keep getting eye contact from one of the moms that is waiting for her son to finish. Sometimes I catch her glancing at me and then the other way around. But we always seem to meet eye contact.

This has happened the last 2 or 3 times I've been there. Admittedly I suck with picking up IOIs but is it a fair assumption that there is some interest there? And should I approach?

Do girls repeatedly glance for guys they're not interested in?

You can open playfully. In those situations I say something along the lines of "I may be intimidating, but I'm not THAT scary. You can still say hi to me. I'll introduce myself, I'm John."

And the proceed with your usual routines or however you run your game.