Obviously, there is a reason why you have made up excuses. You need to take an honest look at what your hesitations are about. Usually, when we do things like this, it is because our instincts are trying to tell us something.<br />
If you can handle taking the time to read a book, you could probably get something out of this book, a book I often recommend, especially to young women: The Gift of Fear by Gavin DeBecker. I would read this before making up my mind to override my instincts and go out on a date with someone much older.
If you are really interested in him why do you feel the need to make an excuse? Are you sure there isn't something about him that doesn't make you uneasy? I knew a guy once that loved to party, he was cute and always asked mw to hang out. Something always came up and so I couldn't. I always had an excuse. I find out after I moved that this guy killed his girlfriend and stole her car and money. So I wasn't aware of my reasoning on a conscience level but luckily my intuition picked up on the fact that something was off with this individual and I was safe for it. Re-examine your motivations for making excuses. If they are truly becasue you are shy or embarresed just say so to him - I am shy around you because I like you- if not you may be unconsciencly avoiding this person for reasons you don't know yet.
Say the excuse was a joke and proceed with the plan.