Is a bbl worth it?

Yes, you are at a lower BMI (20) than it would be ideal for a BBL. I would not "throw away" the fat, but even if it is a small volume, I would do the fat transfer. This might not give you a large buttock, but certainly you will get a better shape. It is difficult to give advise without any photos posted. I prefer the VASER technique for liposuction and fat collection, because it allows me to collect more fat with less trauma to the fat, which means higher fat survival. See a board certified plastic surgeon to see if you are a good candidate for advanced body sculpting. Good luck.

I have had very nice results in thin women like yourself.  Fat can usually be found in at least the love handle area.  The additive effect of the liposuction and fat transfer leads to very nice result.  The recovery time is the same, however with the fat transfer you should not sit on your buttocks for 2 weeks. I hope this helps and best wishes. 

You may not have a lot of donor fat, but you can still get a nice result if your expectations are realistic. The recovery from a BBL is not bad, so if you are going to have liposuction you may as well have injected into your buttocks. Peruse different websites and look for cases like yourself so you will know what to expect, no surprises . . . Thanks for sharing.