If you are just starting out and keeping it under an hour, you are doing really well. Once you get your first done with, you might want to work on a little bit of speed work though. Just go to a local track and try to walk faster for the straight away than you had been. You know. Do some power walking or maybe a slight jog. Not knowing any of personal information, I don't want to presume too much. But I can tell you that 50 minutes is just a touch over the 15 minute mile pace that Disney wants for the 5k that they have every year.
Keep it up!!
Bryan