It depends on how comfortable you are on that little pointy seat I cycled when I was younger, in my 20s and would do the 9 miles to/from my apartment in Washington, D.C. and the Pentagon where I worked in Virginia. At first it was intimidating and discouraging because I rode through Rock Creek Park with the other cyclists but they were all dressed in biking gear and could continuously pedal whereas I was doing a lot of coasting at first, LOL. There was a big hill go get down into/back up from the Park and at the end of the day and mile 8-1/2 coming home, impossible for me to ride up until one day. . . I did! I still remember realizing I had gotten stronger/healthier, etc. because I could ride up that hill without getting off my 10 speed and pushing.

Bikes are extremely expensive though. I would try to find a place that rents them and tool around a bit to see if it is what you really want to do before buying/having one made for you (they are personalized and non-returnable, etc., the bike is fitted to you, specifically) and maybe start saving up for what you want, etc. I might also join a gym and build up my stamina first on the exercise bikes.