At 22, you're probably fine. For Brazilian Jiu-Jitsu, I do think that there is a point at which learning becomes fairly difficult, but I think that there's not really a firm age. I think it realistically has a lot more to do with the health of the person.
If you're a 45 year old and in great shape, then you're probably going to be fine picking up BJJ, though obviously the chances of winning a World Championship is not very good. But when there are recurring injuries, it becomes very difficult to learn BJJ.
The first few months of BJJ are hard enough without serious injuries that make it difficult to train, so I strongly recommend making sure that you're all healed up before training and that you be very careful if you have recurring injuries, as those become really serious really quickly (especially if they're joint injuries) during rolling. But at 22, those aren't going to be serious problems for you.
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Barnett - Toquinho -Werdum - "Nurmie"
Z. Gurgel - Morango - Rocha - Tiequan