Why do I like vegetables now as an adult?

Studies have shown that many children are sensitive to bitterness in food. It's thought to be a leftover defense from long ago to avoid poisonous plants. We grow up, and our tastes change.

It might be because you are starting to worry more about your health, as kids, we don't really see vegetables as a good food, more of a "whack food"

For some of us, our tastes can change as we get older. For example, when I was a kid, the only kind of pizza I liked was plain pepperoni and cheese. But in the 8th grade, I started liking many other toppings as well--onions, green peppers, mushrooms, etc.

It's pretty common. As infants/young children, we actually have more tastebuds, including in other areas besides the tongue. Children are more sensitive to tastes, and can taste bitter things better than adults. This is an evolutionary adaptation which helps us/our ancestors avoid eating poisonous plants when young, before we have learned what is safe to eat.

Vegetables are very healthy for us, but also contain compounds that can taste bitter or unpleasant to a young child, or have textures that children don't like. Most of us eventually learn to like vegetables and as we leave childhood, our "super taster" ability fades. The 'bitterness' in broccoli, cabbage, etc. becomes tasty rather than nasty.

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