Give it a try! My friend just learned and he's 18. As you are riding, have someone next to you holding the handle bars to help support you. Or the method my dad used with me, which is a weird one but worked for me! Have someone get a towel and have it go across your stomach and they are behind you holding the ends. As you ride they use it to make sure you don't fall.
Good luck!
As the others have said you are never to old to learn. A couple of tips for you. Start on a smaller bicycle as you will fall. The shorter the fall...the less pain. Practice on GRASS not a sidewalk or a road if you can with a buddy to help you. Most people that know how to ride a bike will remember how they learned and can help you by balancing you. A local park would be a good place to do this. Before learning to peddle learn to balance. Use a small and I mean small hill to learn to stay upright while you are going down it. Good luck, and I know you can do it! Oh, and I have ridden, raced, and actually use my bike more then my car, and I still get embarrassed on my bike by falling every once in awhile So be humble...most people that would see you fall would be more impressed that you are learning something new...and if they don't...then oh well...you know your learning and thats all that matters.
you are never too old. just get out there and give her a go!
if it will make you feel better ask a friend, one you trust, to help you out and run along beside you.
i suggest using a bike that is a tad small for you so that if you feel that you are going to fall over you can easily put out your feet. good luck!