I can only speak for myself, but over the last 14 years, I definitely have a butt. Several of my leaguemates complain about getting trapped behind it on the track, and I have sent several skaters to the floor with a good solid butt hit.

But it took a long time and exercise to get it. Every cis-girl on my league constantly credits roller derby and our workouts with making their butts look better.
I was overweight, not a lot but definitely heavy, for the last couple of years. I have lately lost over 30 lbs and still have the butt, maybe a little trimmer, but still there. Is it genetics? Is it a result of derby or exercise? I do not know for sure, but the combination of time, exercise, and hormones have helped. I have never been obsessed with the size and shape of my butt, but I will admit that since losing weight, I am impressed with how my hips are "shaping up". I am still old, so I am not expecting to look like a 20-something, not that I want to anymore. But I love that I can lose weight and improve how I look. Plus the compliments about the weight loss has been encouraging.

Not sure if this helps, but there can be hope even if it takes time...
-S