It's true that allergies and intolerances are different, but both can change. Like Jewlz, I used to be allergic to cats, and dogs as well. Terribly allergic, as in couldn't go into a house where one lived for five minutes without a massive reaction. Now, I'm fine with them. However, I never used to get hay fever, but I think I might be developing some pollen allergies. The point is, people's bodies change as they get older, so it is definitely possible to outgrow allergies and intolerances, or to develop new ones.
Good luck with the yogurt, Abbygirl!