Well this will be hard, but trust yourself. You will never be able to compete with your imagination, so don't try. Try not to be intimidated by the fact that he is more experienced than you are, it gives you a chance to learn (I know that sounds strange don't mean it to be).

I can't speak for all men, but most men what someone who appreciates them for who they are, the best thing you can do is try to show that appreciation in small ways, making him a sandwich little things like that will go so far in your relationship. Just look at his life, the things he does during the day, try to figure out things you can do to show your appreciation for him. If he has to work late and you know he is going to be hungry bring him something to eat, if he is tense give him a shoulder massage. Now showing appreciation for your partner should work both ways, he should be doing the same things for you.

Being confidant is much easier if you feel you have a bit of control of the situation, and in this case you do, small acts can produce big results. Show your appreciation but don't become a door mat, or allow yourself to be taken for granted, he should show his appreciation at being so lucky to be with someone who would treat him so well.