Am I able to have a skinny BBL? 5’0” / 90lbs / BMI: 17,7 (Photo)

Hello dear!
Thanks for the question and provided information as well.
Based on your pictures, you are a great candidate for liposuction with BBL, and I think you'll get very good results.
Liposuction allows your plastic surgeon to transform your entire shape. You can improve your abdomen, back and flanks, and of course your buttock, to give you a nice heart shape.
In general, you need to be physically healthy and at a stable weight, have realistic expectations, be a non-smoker and your BMI needs to be 33 or less.
l recommend you to make an appointment with a board certified plastic surgeon to talk about your goals and anything you need to know.
Good luck :)

Everyone has some fat. The question is if you would be happy with what is achievable with the amount of fat you have. I don't think there's much point in gaining a lot of weight preoperatively as your body will tend to revert to its normal weight after surgery and some of the transferred fat may dissolve. Maintaining a higher body weight will require a permanent change of lifestyle and might not be sustainable sometimes. The desired "hour glass" shape starts building up with liposuction (for example making the waist slimmer and the buttocks proportionally bigger) and is only complemented with the fat transfer.