Hello, would have a few questions especially about the 125cc class

Hello, I am in possession of the driver’s license A1 (at that time still 1b) and am 37 years old. I made the ticket in 1994. Now you can drive a motorcycle of the 125cc class, I can drive it open, but what exactly does it mean? Have 40 km up to work and have thought about adding a 125er so that my car does not “eat” so much km. Is that worthwhile from the cost/benefit factor, or is such a 125er rather only what for young starters? After all, such a part already costs a rod G eld, both purchase price as well as insurance etc. I itchts also a little in the fingers, I drove at that time with a 50cc moped, is still already 15 years ago… MfG Mirko