125cc as a first bike

Does anyone have any arguments for and against buying a 125cc as a first bike? I’m only asking this because in some countries in Europe you cannot get licenses for higher power bikes until you get older, and I want to get into riding as soon as possible. My main point is seeing if it is worth waiting 2 years to start on a 400cc or if riding a 125cc at 18 is actually worth the money and investment.