You have the power to decide how fast or slow your car goes, so you also have the power to control how fast your bike goes, especailly once you are familiar with it. The two major roads by my house never have bikes on them, it's just too dangerous. The corner curbs all now have the wheel chair acessable ramp, but it points directly at the street and has curbs on both sides instead of those nice wide smooth radial ramps. I'd break my neck trying to get on the sidewalk. I spent a Saturday afternoon getting used to my bike, discovering the city I live in in a whole new way, and finding the side streets with less traffic, and fewest stop signs.
Even going slow you are going faster than most "cagers" expect so you have to drive defensively.
will they let you exchange it for a smaller one?