IMO its the worry itself which causes the bad trip not actually the repressed/bad memories. I know lots of people with bad childhoods who have great trips, but anybody who is anxious or worried about anything on the trip will have a bad time.

If you are in a good place surrounded by good people and you are happy, then it should be a good experience. If you go into it worrying about what will happen then the drugs will compound that anxiety, not relieve it.