Fair play to you - you've opened your heart . You're singer who sings in tune - very decent accompianment on guitar - and have received wiser advice than I can give. The formula which seems to work is to keep the patter funny BETWEEN songs , or sing a funny or a thoughtful song.
There ARE FUNNY Songs in the blues idiom (e.g. How long do I have to wait,) and singalong "blues" e.g San Francisco bay bluesbut.....
I bet you know hundreds of songs . Time to sit down and decide where you want to be , you speak some German, and get the odd laugh. In Germany they're quite passionate about all things Irish so think about That ( including all the English songs which are claimed to be Irish.
If you're going to do purely Comedy, step back - and get a stonewaller of a set - well-reheasered Ad-Libs et al.
Best of luck - tweak the whole set - dump somethings and import some things and take your time.
If a stranger at the bus stop, wants to tell you jokes you get a bit frightened - same with an audience , build up a relationship / bridge with them first.
Good luck Al., you love performing so and I hope it all works really well for you after you you've opened your heart.

Betsy