I am petrified

What ga said. But also reverse park your car for a fast get away if necessary.

I can understand the cold feet; it's bound to be daunting, but at worst you will have been out to lunch and at best you will really enjoy it. Brace yourself and go for it I say. (One of my foster lads met a lovely girl this way and three years later they were married.)
p.s. Do please come back and tell us how you got on.

It's lunch, so just chill out! Even if nothing comes of it you will have have been out for lunch and have made a start. Wear whatever you feel comfortable in, smart trousers and a jumper would be fine. Just chat - if the conversation runs dry just ask some questions. What does he like to do for holidays? Read? Hobbies? TV? Theatre? Always useful to find out about his family and friends - good pointers to how a person makes and keeps relationships. People always like to talk about themselves. Open ended questions work best - what, where, when, etc. You may make a new friend or not but you won't know unless you try. So have a nice lunch and see how it goes.

Been there, done that. I agree with everything others have said. I was also told, reverse park the car in case you have to make a run for it, but that is really unlikely.
I'm still with the guy after 15 years :-)

I would just treat the meeting as if you were going to meet a new woman friend you'd been chatting to, because that's all it needs to be. Just meeting a friend and seeing how you get on.

Just wear what you would normally wear for dinner out. Don't do anything you wouldn't do normally. He must get to know you as you are, or you'll be acting a part for the rest of the relationship.

Good luck and have a nice time!

However, I have no experience of this sort of thing, so I will follow the thread with interest.

Relax a little Rolande I know its a big step for you but it is just one date. Wear something smart casual which you are comfortable in. He is lucky to be meeting you so enjoy the evening, if there is anything about him you don't like no second date. Be safe, tell someone where you are going and arrange to call them when you get home. Don't accept a lift ensure you have transport available. Enjoy.

Well good luck.
Do make sure you take all the necessary safety precautions. A prearranged phone call from a friend in the course of the meeting is a recognised way of getting out of a tricky (or frankly boring) situation.
Meeting over a meal is probably a very good way of forming an initial impression. He may be as terrified as you OR he may be a dead loss (older, false teeth, toupee, lecherous, thoroughly boring) or just nice but dim.
Don’t give away too much information about yourself or your family and (dare I say it) don’t expect too much.
But do let us know how it goes!