GOOD ON YOU!!!!
Keep at it! It gets easier, then the quads stop burning, then you go farther, then you start looking for hills because you miss that burn, then you realize you need new dud's but accidently buy the wrong size cause you didn't realize that all that riding really WAS burning calories, then maybe you start looking for a new shiny bike , and then you buy a computer so that you can count the miles you are logging, then one day you realize that you are a whole new person- and you LOVE it!!
Welcome to your new life!
Enjoy the ride...
Denise