Nope! The Steam version should allow you to select between "NSFW Off" and "NSFW On" at the start of a new game.
Depending on the route, the NSFW content might happen later in the story than others, like Dahlia and Will. You'll know you're in NSFW mode once the 2nd CG pops up in every route after the first kiss. SFW mode will only have the kiss CGs.