Honestly, if this plan actually works with the 18 year old Chiaki. It'd be a good idea, remove the whole loli aspect, just make her somewhat petite. She as far as I've played seems like a shy character, and the whole shy aspect + petite would make sense.
Ignore some of the weirdos here who want to see the current version kept and made lewdable. This whole remake of her character would do you good in terms of future monetary gain, especially if you can make it onto steam. Mainly because I guarentee some people don't trust itch.io or patreon enough to give some money for the game on here. And expanding onto steam would sorta introduce the game to people who've never heard of it, and don't wanna buy it on here. For those reading this who disagree, think with your brain not your dick.