Can I do BJJ with no athletic background?

Unlike sports that require years of childhood development, BJJ can be learned effectively at any age and from any starting point. People who have never played a sport in their life have gone on to earn black belts and compete successfully. The initial period will be more physically challenging without an athletic base, but the learning curve for technique is the same for everyone. In fact, people without athletic backgrounds sometimes have an advantage because they do not bring bad habits or overreliance on athleticism. They learn to use technique from the start. Your body will adapt to the demands of grappling over time, developing the specific conditioning, flexibility, and coordination that BJJ requires. The most important attribute is not athleticism but rather consistency and willingness to learn.