A local archery dealer measured my draw length to 29". He told me that this is not the same as the length of my arrows.
I wonder how long an arrow has to be?
The answer is pretty simple for the general rule: take your draw length and add one to two inches.
You do that because you might draw a little bit further than your actual draw length. This is pretty dangerous cause the arrow might penetrate the hand which holds the bow!
I would recommend to generally add 2 inches for an absolute beginner. This would be 31" in your case. Why?:
Later on you want to "tune" your arrows. It's a process of "taking a little bit off the shaft" and "shoot the shaft". In that case you have a very individual arrow length for a particular setup (setup = bow + arrow + shooter).
This is how you do it: https://www.youtube.com/watch?v=OiSoF8grd3w
However, it's not worth worrying about this topic as long as you don't group safely in the size of tennis ball.