Why do I have an unusually large stomach for my body size?

I'm 5'0 ft tall, 110 lbs, 19 years old, female.

Everywhere else looks skinny but my belly is really big.
My belly used to be flat. My body weight was evenly distributed. Now it's not. Don't know why.
My sis weighs more than me but her belly is flat. She's more active though.

I was thinking it could be because:
- was sedentary for 2 years.
- disordered eating.
- went on 2 extreme diets that basically told you to overeat. (did 30bananasaday/rawtill4 diet for a few weeks and low carb high fat diet for 1 week. ate too much carbs for the first one. at so much fat from the second one.)
- irregular sleep (sometimes I would stick to a consistent sleep schedule and sometimes I would sleep late. drifted between the two. and once in a while i wouldn't sleep at all.)
- used to be depressed and suicidal. and had anxiety.

My weight is the same as before but my body looks different now. My body weight distribution changed. My body looks normal before. My belly used to be flat.

But now:
- exercise everyday (stretching, cartwheels, handstands, and walking 1 hr)
- eat healthy (whole, plant based food. fruits, veggies, rice. can show you my food journal. also been eating more normally.)
- been fasting to try to lose the belly fat
- sleeping better now but still working on it.
- been stressing about food a lot but not depressed anymore. still have a little anxiety. but mostly happy or neutral.

Is it because I just ate too much?
Am I just fat and do I need to lose weight?
Maybe i just need to keep exercising and eating healthy for at least a year to get rid of the belly?
Do I have Cushings disease or metabolic syndrome?