I think it is a good idea to have a bike that fits you. Hopefully you have a high quality bike shop nearby that can assist you. Bear in mind that as you develop your riding skill, strength and fitness that you may well find that you are happier with a less upright position. By the time that happens, you will no doubt be addicted to riding and will join the N+1 mindset where N is the number of bikes you have and N+1 is the number needed (sadly, not always a joke).

As far as tires go, there has been a three decade long obsession with very narrow tires at very high pressures. Finally, someone (actually a fellow named Jan Heine) did some proper experiments that demonstrated that those skinny hard tires are not only less comfortable to ride on, they are actually slower than wider tires. For any given tire, wider is faster and more comfortable. Bear in mind that there is a wide range of quality available in terms of tires and that they can be quite expensive. My preferred tires cost about $75 each, but I ride very long distances far from any services, so they are worth it to me.