Is it normal i lie to my girlfriend about my disorder (pica)

I’m 23 and I have pica, which means I eat a lot of things that aren’t food.
(Mostly wood, chalk, rocks, ice, erasers, wires, glass, rubber, leaves, roots, plastic, lots of coins and paper money, cotton, fabric, pencils, string.)

And I haven’t told my girlfriend it’s a real problem yet, and really I lie to her a lot about it. If she ever asks about an object that I’ve eaten and she doesn’t know, I lie about where it is. I lie about where I am when I’m attending therapy. I lie about the medicine I take. I’ve even lied about a hospital visit. And anytime she has her suspicions or catches me trying to eat something I lie about my intentions. Obviously she’s knows I “like to chew” and just assumes it’s nerves or a quirk, she has no idea the extent of my behavior.

I hate lying. I really do. But it’s weird as hell to explain to people, and even harder to hear over and over “why don’t you just not do it”
It’s goddamn embarrassing enough to have any health/mental issues, it’s 10x harder when it’s something that can be so easily turned into a joke.