Don’t even try recovering that account - it’s a security nightmare. Google’s recovery system depends on previously set recovery methods and device recognition. If any of those 25 students added recovery phones, backup emails, or used devices that are still logged in, they could get back in even after you recover it. Shared computers are especially bad since they cache credentials and browser data way longer than you’d think. I’ve seen old login sessions stay active on public computers for months. Just create a brand new Gmail account with a totally different username. You’ll get a clean slate without all the baggage from when everyone had access. Save any important contacts or info you need, then start over with proper security this time.