I can understand that. It's hard when your brain is telling you no. But here's the thing. Your brain isn't always logical. It likes the status quo because that's what it has learnt to deal with.
As well as that, it is a possibility that this idea won't be "THE" Idea. Lord knows I've had plenty of those. But that's OK. Because you're one idea closer to finding and building that spark that you can carry through. Webcomics challenge you in a new way that is scary at first because the Internet is a scary place to expose yourself to.
But you have a supportive space here on the this forum where you can get help to improve your work. There are smaller platforms you can host on that are more suited to new/experimental projects if you want to give yourself room to grow.
Take your time and let us know when you start because I would love to see it. 