So I met a girl who liked being fat and wanted to dive into feederism with me. The problem is she wants to take it slowly since its new to her. Do you guys have any recommendations?

Just make sure she has her favorite foods on hand at all times. Take her out to eat frequently, offer to pay for her groceries/snacks. If she doesn't have any other people in her life supporting her gain, it makes it harder for her to stick with it. Ideally she should be exposed to women online who have gone from thin to fat, and sites like Curvage but if you're the one who introduces her to those sites she might think you're a porn addict and be offended/turned off. Maybe best to start with YT documenteries about feedism instead, then let her google it on her own. Whatever you do don't direct her to a specific feedee model as she may get jealous if she thinks you're subbed to that model's site, etc.