I was growing up with my grandparents, who still had a few pigs, chickens and I always had cats. I was always outside and in the forest, but I'm still allergic to pollen of grass, flowers and trees, also surprisingly to cats and dogs - and, which is more shit - to bees, wasps etc...

Although from young on I just ignored the allergy regarding cats and dogs. Now I'm still having a cat (a rescue, who lives in my apartment) and besides some heavier reaction to scratches, I don't have any problem with cuddles and sleeping in bed with him.

I think my overly concerned mother (young single mother) just went to the doctor with every little thing I had, and all the antibiotics I've got, have fucked up my immune system.

With the pollen thing I've got syringes as a child, so at least I got rid of the allergic asthma. And the older I get, the better it seems to get.

But with cats and dogs, I was just stubborn and it seems it worked out ;⁠-⁠)

Still, I was always outside playing in the dirt and still got a shitload of allergies...

there is also a causation question. I'm similar to you, I don't get sick much so I don't have much reason to be obsessive about cleanliness (of course I am hygienic and practice normal food safety). but my wife gets sick often and that causes her to be extra super careful about foods she eats, cleaning, hand sanitizing, etc.