Please don't worry about your English. As long as it is understandable (and machine translations adapted to context those days can actually give surprisingly good results), you'll get to the point where you become fluent in it should you choose to keep it in English.
A random thought: Ren'py allows for multiple l10n (localization), so you should definitely add your native language as well. More work, but if it makes you feel better...
"Bad English" or Engrish as some call it in the west should never stop your creativity. Many content creators have transcended language barriers and they are shockingly good at it now, since they've been using it every single day. You can trust a translator's word on this - this can't be worse than a game translated back and forth with massive loss of context.
Your posts alone are more than enough proof that you can 'get your shit together' and you just need more confidence and practice. So don't let that stop you and just warn your userbase beforehand, you'd be amazed at how many native speakers or even writers with a master's degree have metric fucktons of typos and terrible grammar because they don't proofread their work or don't do it properly.
Yeah, getting lectured on confidence by a depressed poster with low self-esteem is kinda ironic but bear with me. I know how you feel about censorship issues.
tl;dr (too long; didn't read version) - Don't let that stop you! Make what you want to make, be passionate about it, and let your mind roam free while you still can! I wish I could still do that.