First of all, we have to confirm whether the following dance is aerobics, because aerobics generally has a large difficulty coefficient, and there are difficult movements such as splits. If it takes three hours, the amount of exercise should still be a little large. But I think you should do aerobics or cheerleading. If this is the case, I suggest you do some activities before exercise, or you will easily get knee injury or ligament strain. Three hours may be too long.
In fact, if you want to lose weight, you can do some yoga or core strength training (Baidu will do it), and the effect may be better. But aerobic is also good, it can make you happy!