Having a colonoscopy @53. If I have it done in the am will I be able to attend a function at night and how long before I can eat and drink.

I think so. If your colonoscopy was uneventful in the morning, you may attend a function in the evening, but better if somebody drives you, and you can start eating and drinking, do not overdo.
Sedation. You will receive conscious sedation (typically versed and fentanyl) which can be pretty sedating. While most people do just fine, some can have pretty significant sedation and personality changes for a short period of time. You will be able to eat and drink quite soon after the procedure, as long as you are not having nausea, but as for being ready for a social function, i would caution.