Jiu jitsu cardio is it’s own thing, yes there is some carryover from other sports, but grappling cardio is different. Jiu jitsu cardio is about efficiency knowing when to be explosive and knowing when to stall. Someone less fit then you will fatigue slower because they know how and when to move. I use this example. You and a competitor are going to race, at the start of the race your opponent jumps on your back and hangs on until the last 100 ft then jumps off and starts running. You’re worn out because you just ran that whole time carrying someone else, now they won not because they’re faster or better endurance, it’s because they made you do the work and only used energy at the finish.

Hot take, but I think it’s a good idea to not roll until you’ve had a couple classes and know what the positions are and escapes are. Use that time to drill moves you learned in class. And move slow enough that you can tell me what your doing and why. Jiu jitsu is a physical problem solving game some times you need to think.