It’s not uncommon at all, there are even adults who do it !
You may find this article helpful
https://www.healthline.com/health/eating-boogers#tips-for-stopping

Telling her off every time you see her do it – it will eventually work.

I explained to my 3 year old what snot is and therefore how it is really dirty. I think he kinda got it after that. I always try the method of honesty – kids are pretty smart (even if they do pick their nose and eat it)

Have you tried that nail biting nail polish that tastes terrible? Not sure otherwise!

lol oh my gosh! kids do that hey! try to gently remind them that it is not food lol.

Lol if she’s gonna eat it, she’s gonna eat it ^.^
My uncle told me when I was little that if I picked my nose my hair would fall out. My solution?- Put my hand on top of my head to hold my hair in while I was picking my nose

reinforce positive behaviour, keep the message simple, and remember it is stages not ages with kids!

We have told our kids it is gross, I even went to gp for advice she said while it is gross kids who pick and eat tend to get less sick. We still pull them up when doing it but have found the less attention we draw to it the better

We have told our daughter it’s yukky. She hasn’t done it for a while