M.J.
One of the best decisions I made years ago was losing my ponytail only long hair and getting a real haircut with style (a ponytail is not a style). No one ever complimented my ponytail but I get positive feedback all the time about my hair cut now. I love having shorter hair. Short doesn't have to make you look older. You just need the right style. Maybe opt for a bob that's just above shoulder length at first and take it shorter next cut if all goes well.
I agree with the others on finding a great stylist who will be candid about what will/won't look good on you. You also want someone who keeps up on trends so you don't get an old-fashioned cut. An Aveda salon might be a good place to start, if you don't already have a stylist in mind.
Good luck!