So much good advice already, and I was in exactly the same predicament as you a few years ago, in that I knew that eventually I was going to try the real thing but was very nervous about it.
I did alot of research on here and other sights, mainly forum type sights, I found fabswingers very useful.
I had tried and enjoyed loads of toys, both as solo playing and with others, so I knew that I had the ability and capacity so to speak!
So to progress to finding and actually meeting someone that would be understanding, respectful and gentle, was not as difficult as I had thought it would be.
The hygiene thing is also extremely important, as at least you have the confidence that in the heat of the moment it's not going to get a little embarrassing! And just take it extremely slowly with alot of lube, and try and relax which is much easier said than done.
I was very lucky, the guy I met was an experienced top, and very understanding and also, and he won't mind me saying this, was of average endowment! So it wasn't too frightening. I don't use poppers, as some people do, but apparently they are supposed to relax your muscles a little, but I just found they gave me an horrendous headache.
And I think the biggest surprise for me was how different a real cock feels to all of my toys in a good way, I find the sensations much more intense and exquisite, and it is so much more erotic and naughty.
So very best of luck, and I hope you enjoy yourself.