Yes, seeing your characters slowly change with your art style's totally natural and definitely nothing to worry negatively over! It's exciting to see improvement but yeah, at the same time, you worry it could turn off readers who decide to go back and read your comic from the beginning. I don't think that it does!
There's about a year of work in my comic and wow. The first page to the most recent page has virtually everything changed in it. I moved from 100% traditional to half and half (introducing digital inking) but the characters, the backgrounds, the panel layout, all so different! I'm still doing a bit of wrestling with my technical skills so I'm sure this time next year, it'll be another huge shift but that's COOL.
And it's always really fun to look at how an artist's hand advances -- the comic format is SUCH a rad way of presenting a body of work! You're building something awesome as a timeline, yo.