I agree that the longer we hold on to the past, the more difficult it is for us to move forward. Yet, for our past to have held greater value, we need to at least have learned the lessons it taught us.
There are no guarantees out there. We learn best from our mistakes (hopefully!) So I guess MY answer to my own questions is: put yourself out there but keep your expectations in check. The possibility of disappointment is always there. However, that only affects us in as much as we allow it to.
You can’t control the world or what people do, you can only control the way you respond and react to what happens around you. And make mistakes.. so what?! It's not the end of the world. Pick yourself up, dust yourself off, and move on! (so cliché!!)