Adaptations aren't inherently a bad thing. What matters is that you tell a good story and you tell it well. That's why Disney is successful.
It doesn't make you any less original because if you're staying true to the story that you want to write (and by virtue of being you, it'll be a story only you can write) then it will be a unique tale, even if it uses familiar monsters.
In terms of "getting out there". In my experience the only stuff that creates lasting readership and success of any kind is learning storycraft and lots of practice writing stories.
It's not that fact that's its an adaptation that will be the reason it does well, but it will be how well you tell your reinvented version of it