Writing with a 73 year old daddy. What to look out for?

Potentially im (28) going to a hot bear grandpa next week to suck his cock and service him.
I really like the thought of beeing with a dom old grandpa and sucking his cock but i chickened out of many opportunities so far becuase im shy and more bi then just gay. Like i enjoy women of all ages but with man they got to be 65+ otherwise its not my thing.
He doesnt like anal so i wont have him in me like id like but he would like me to strip naked at his place then suck him. He probably would like to suck me too. He said hes quite experienced and reassured me we only do what i like. Plus we had some fun spicy chat.
So how would you proceed? And daddies have some experience how they handle situations like this? Hes quite dominant what i like but im not sure im going to be just nervous as hell.