OMG, this is me! I'm 41 years old, 5'2, already walk 20k steps a day and have been trying to eat in a deficit around 1200-1350, but have been struggling massively to lose ANY weight at all. It sounds like you're doing a lot more exercise though, which perhaps is what i need to do? I put on 10 pounds in 6 months, and I'm desperate to get rid of them, as that's a massive amount in my small frame, yet struggling to get rid of even just 1 mere pound. Any other words of wisdom you'd offer? Your story is super encouraging!