First off, congratulations on getting out there and doing something. I had been sedentary and overweight for years, and one thing I am reminded of is that I didn't get that way overnight, so I can't expect to lose weight and get fit overnight (I've lost over 100 lbs through eating less/better and moving more). So Rome wasn't built in a day.
My yoga instructor often reminded us to respect our bodies and recognize and accept that they are not the same each and every day. Our energy levels are different, or balance is different, etc. So recognize it, embrace it, be thankful for what your body is able to do today and don't compare to yesterday or tomorrow. Love yourself in the state you are in at this moment.
Hang in there and keep up the inspiring work.