Single speed or fixed gear can be exhilarating to ride. Need to choose the gear size so that you can just manage the steepest hills that you encounter on a regular basis, then the rest of the journey will be fun. If in a hilly area, single speed (free wheel) might be the best option as descending on a low fixed gear can be tiring and takes more skill than you might imagine.
Count the teeth on the front ring and the rear sprocket and we can advise if that is a sensible set up. Easy and cheap to get a smaller/ bigger sprocket.
Happy riding
Keith