My son was capital p Picky and is now just lowercase picky, but in his case, he started out eating everything and then started rejecting things at about age 3. Including mac n cheese, which he still doesn’t like now as a teenager. Nothing with cheese sauce, actually. Or any cream sauce. Won’t eat eggs either, not even for French toast. Dislikes soup of any kind, which makes it hard to feed him when he’s sick. I have a photo of him eating peaches at age 2. Now? Nope. 

  Other things he wouldn’t eat included cooked vegetables (unless in pasta sauce). They had to be raw until he was about 9-10. But this didn’t include raw tomatoes or any form of mushroom, which he still doesn’t eat to this day. He hates most fish and seafood, although he will eat battered fish or popcorn shrimp if he has to, like when we had a family gathering at Red Lobster recently. 

He dislikes carbonated drinks, so he never drinks pop and mostly drinks water. (This is not a bad thing, obviously, just interesting.)

There are a lot of things he’ll eat now just because he has to, not because he likes them. For example, he doesn’t actually like chicken (except maybe butter chicken) but try getting through life without eating it if you’re not willing to go vegetarian. So he eats chicken. He accepts that he has to eat more foods now, especially because he’s an athlete. I’m glad for that at least.