There are lots of older homes in St. Louis with original pine hardwood floors. Pine is very soft, and therefore is more time consuming and a little more expensive to refinish. It doesn't take stain well, so unless you go with a darker stain color, it may be blotchy. We recommend that if it's in decent condition, a clear sealer and urethane might be the best bet.
According to Garden Web's Old House:
Pine and hardwood are two different animals! hardwood usually has 2" wide boards, pine usually is 4" or larger. hardwood is, well, hard, it doesn't scratch as easily, so it held up very well. pine is soft, it will scratch very easily and the covering will flake off. well done and quality is EXTREMELY important, and even then care will be needed to keep the floor looking good. rollerblades are out! ;-P use coasters under furniture and use the felt kind, not the plastic kind. hard shoes will even damage pine floors. make it a "leave shoes at the door" rule and you can be very happy.
You can trust Professional Floor's 35 years of experience in refinishing your older, pine floors.