Yo, congrats on getting your license! So look, honestly both bikes you're looking at are solid, the guys are right about that. I ride around a lot for my mechanic job and I see tons of 125ccs pass by, so I'm speaking from experience here. The CB125R is really the safe bet, Honda is loaded with reliability and honestly I've barely ever seen one break down. Maintenance is basic, you can do it yourself if you want, and insurance won't kill your wallet too bad. It's more neutral style-wise, nothing crazy to look at, but it gets the job done.
The YZF-R125 though is a bit more fun to ride, it's got more punch and clearly it looks way better. If you want to feel a little "sport bike" vibes it's the one. But you gotta be aware that insurance on sportbikes is a bit pricier, not huge but noticeable. And then it needs a little more attention maintenance-wise, nothing crazy but good to know.
My honest advice? It depends on your use and budget. You wanna max out reliability and spend less? CB. You want more thrills and you can put a bit more down? YZF. Otherwise check out the Kawasaki Ninja 125 and Suzuki GSX-S125 too, there's good stuff there as well. And once you've picked one, look for a decent used model rather than new, you'll save a good chunk and on a 125 it's more than enough to get started.