Usually a being late for something dream is a warning about making a promise or pact that you may not be able to keep.

If you're like me, you are a good listener. And being such, a lot of people come to you, just to vent or bounce ideas off of....but sometimes they want to 'un-load' something and want you to keep it a secret.
If it's about a birthday surprise, no big deal. But if it's something 'serious', it might be in your best interests to tell them that you don't wanna be the keeper of that particular secret & are making no promises.