I think I'm eligible to weigh in on this since I was issued a MacBook in high school and then went on to work IT later.

Do not, ever, under any circumstance, for any reason, use your personal device for business. Whatsoever. This includes school. If your job requires you to install an application on your phone, they better provide you a phone with it installed. If your school wants you to use a chromebook they will provide you one and you will use it. It is never a good idea to put these things on your personal device for convenience. The reason for this often comes down to security. For employers, they want to make sure their data is secure, and will retain the rights and the ability to remotely wipe or disable your device. If that's the work phone, who gives a shit. If that's your personal phone, suddenly you are the one who very much gives a shit. For schools, they want to make sure their students are properly monitored and cannot cheat or get up to illegal shenanigans, so the devices will be locked down tighter than Alcatraz and they will likewise retain the rights and the ability to remotely wipe, disable, or take control of the device. And some of those lockdown programs they install will put entries in your registry or something that causes them to be pretty goddamn near impossible to ever get rid of without a full wipe and reinstall, and frequently make it extremely difficult to wipe and reinstall without the assistance of the administrator. School IT would be able to fix this for you once school is letting out, but probably the only way they do it is by wiping your whole hard drive, or at best, restoring an image from before the beginning of the school year.

And that's not even getting to the point where if all the students have a standard issue chromebook and one person has a much nicer one, it's not a matter of "if" but "when" it will be stolen or broken.

Honest to God you are both going to be miles better off just putting up with the shitty one and keeping the good one at home. I promise with every shred of my cold shriveled ex-IT heart that that's in your best interest.

Edit: Just realizing, chromebooks don't really keep shit on their hard drive do they? My prior warnings still apply, but if there's nothing on there you're really worried about and you don't mind if the chromebook gets nuked and resurrected, go for it I guess. This warning was mostly in the perspective of the MacBook that I used personally, or phones for employers which is relatively common. Just be aware that you're handing the school IT the keys to the kingdom for a while, and they'll pretty likely be able to spy on anything you ever do on that device.