The only way to get over an obstacle is to go through it. Many of us (me included) tend to think about all of the things that could go wrong rather than all of the things that could go right and wind up not doing anything at all.
It's understandable to be scared, but if you don't at least try you will never know what could have happened. It's okay to make a mistake, just as long as you learn from it. So, rather than living with the woulda, coulda, shouldas why not just feel the feeling and let it go and then do the thing!!