Following through on a commitment you regret teaches you to make fewer of them.

Keeping a promise you have gone cold on teaches you something no amount of resolving to be careful can: exactly what a careless yes costs, measured in hours you do not get back. That lesson arrives through the body rather than the head, which is why it stays. Backing out protects the weekend and leaves you none the wiser.

Do the thing you said you would, properly, and pay attention to what agreeing so fast cost you. Then set a rule for next time: nothing confirmed on the spot. Collect the lesson while you are already paying for it.