Honestly, the artist will always see more differences than the reader. I'm not saying you haven't improved, you definitely have, but the difference is much less drastic than you fear. It's not jarring. It's an organic, slow-process growth comic artists go through, and as a reader you don't notice it when you're reading page by page, because the difference between pages is so small. Drastic differences between first and last updates don't begin to show up until pretty far into the story.
Also, each new page is going to be slightly better than the previous one. So where do you stop? Once you've "fixed" the first chapter, it'll be on the level of the last chapter, but what about the ones in between? The second will be the "worst" one now. Then you fix that one. Then you have two "better" chapters in the beginning, and then the rest looks "worse". See what I'm getting at? You risk getting stuck in an endless loop! And your story won't progress!
Another thing to keep in mind is that your readers are also focusing on the story, they're not sitting there thinking about every little line on the page. In general, they'll only spend as much time on the page as it takes to read it and get the gist of the images, and then go to the next one to progress the story!
The art of your first chapter is no turn-off in my opinion, so don't worry and keep pushing forward! Your readers will appreciate having more story to read way more than a hundred versions of the first chapter (;