I would advise in not going for that 18-30 demographic right away and promote the film through a more popular film community. Namely speaking,
Atom Films.
Fact of the matter is, premium short-form content doesn't generally do well as a viral video, for a variety of reasons. Not saying they can't go viral, but the instances of which just don't happen. Most people want to find premium content by any way possible, but there either has to be some degree of familiarity (heard of the film, haven't seen it) or a strong word-of-mouth following for that to happen. Think of like HBO TV shows, which generally pick up steam in viewership when other people keep talking about it. The trick is to get that initial push. Even if you send the video to friends/family and they think well of it, it likely won't pick up enough momentum for it to build a stronger following.
So, I'd concentrate on a film community like Atom. It's likely that the viewers will take the time to watch it and offer some constructive criticism. Also, if it's a really good movie, you're more likely to get better traction amongst those people you want to target initially because you have a wider following of people willing to talk about it.