It’s a question of balance.
If you tell a joke that causes other to quirk their lips into a half-grin while you are rolling on the floor, holding your sides, laughing uproariously, you are going to look like an idiot.
If you tell a joke that causes your audience to Roll-On-The-Floor-Laughing-So-Hard-They-Pee-In-Their-Pants, you are certainly entitled to join in the laughter.
There is no rule against laughing at the humor of a situation that you, yourself, have described. On the other hand, as the provider of the entertainment, it is considered unseemly to also lead the cheers for your own performance (which is what it looks like if your laughs drown out the laughs of your audience).