There's a place for this. It is a moped where I live. Not Class I or III because it has a throttle. Not Class II because it exceeds 20 mph. So register it and buy plates. That's $140 one time, and $41/year in Illinois. You'll need mirrors. Helmet is optional. Our law is unclear of whether you can ride it with just a automotive license, but a driver's license is required for sure. To be safe, take and pass the motorcycle test. Road test is easy on a moped, but you do need to read up on the laws.
Motor vehicles require insurance too. You want that anyway. Stay out of the bike lanes, and have fun.