I am fairly new to Pathfinder Adventures and still playing with party ideas. If I start a new set of characters in story mode, are they able to start at the lowest level or have to play Heroic/Legendary depending on which scenarios my first group finished. (When I tried, it didn't seem to offer the lowest option and I thought Legendary might be tough for a group just starting out with no feats or cool items) Thanks.

Click the skull and chose the green aka normal difficulty. So in short it is possible, but you don't have to.