Is $3,500 to install bathroom fixtures and vent fan a fair price?

My 5x9 bathroom has been demo'd, and I've picked out new fixtures and a shower, costing about $3,000 for materials. I'm planning to do most of the installation myself, but I'm concerned about installing the rectangular shower's drain, as it needs to align with the existing plumbing from a round corner shower without moving the main lines. My house is a 2-story, 2000 square foot home built in the late 1880s-1890s, with a mix of copper, iron, and PVC plumbing. The shower supply line is copper, and the sink and toilet supply lines are iron. I'm assuming the drain line is iron. This is a second-floor bathroom, so I can't access plumbing from below. I'm worried that if I start replacing pipes, it could lead to breaking other pipes, requiring extensive and costly wall and flooring replacement.