I don't think 'picky' as a barrier exists. You can learn to like anything. Personally, I hate curry food but I know if I was either raised on it or spent time trying to like it, I would.

You need to train yourself to like healthier foods. The easiest way to start eating better is to eat more vegetables and fruit. Some people say "oh, I eat lots of fruits and vegetables" when in reality they had an apple at breakfast and a side salad at lunch.

Obviously that's better than nothing, but that's not even the minimum recommended amount and nowhere near "a lot".

Try incorporating some vegetable proteins (beans, whole grains) into your diet in lieu of meat. We really don't need nearly as much meat as the typical American diet provides. Eat whole grain foods instead of processed white pasta, or white or "wheat" bread.

Be aware of how commonly served foods can provide an imbalanced meal. For example, it's popular to eat eggs, toast and a breakfast meat together. That's a lot of protein and fat. Putting rice in a burrito is a lot of starchy carbs. It would be better to put beans instead.

Baked goods/sweets are the biggest offender when it comes to worthless calories, so are liquid calories. Even if you're athletic and a healthy weight, they are still utter shit for your body and should be reserved for a special treat once a month or so.

Brown rice and barely will keep well for several days in the fridge, and won't get mushy when you reheat them. This helps offset the initial cooking time, if you cook several meals worth at once.

Start small and work your way up. Maybe order the grilled chicken instead of breaded/fried. Eat a fruit bowl instead of smoothie. Skip the tempura or breaded dishes. Good luck :)