I know I have said this about a million times, but ballet truly is for everyone. Not everyone wants to take it to the level I do, sitting exams and so on, but if it's just recreational fitness you're after, then it really is one of the best exercises there is. Even a simple barre routine will help flexibility and core strength, as well as coordination. Centre work helps balance, stamina and focus and again it works that core strength.
Whilst you won't really lose weight doing ballet because it's not very aerobic, unless you take more advanced classes where jumps are involved, but you will become more in tune with your body, your posture will improve making you seem taller and more posied, and you'll better your flexibility which helps you in your old age - the stiffer you are now, the worse it'll be when you are old.
In terms of ballet as a profession, yes it's definitely only for the young, but for recreational purposes it's truly for everyone. To prove this, on Monday a lady came to pointe class, who was easily in her early 70's if not older. When she came in I thought perhaps our teacher was off and she was the replacement. A tiny little lady, slightly hunched, but with that undeniable poise of a former dancer. I assumed she was now a ballet mistress. But she sat down, took out her pointe shoes and got ready for class! I was pretty astounded. She managed everything way better than I could. Her feet still had a beautiful arch and she just basically rocked the shit of the class.
I get terribly frustrated in class, pretty most days, because I'm frequently doing stuff that's above my physical or mental capabilities, leaving me angry and annoyed. Pointe class lately has been pretty awful as I feel I just fail at everything. I mostly have to stand by and watch, just to be able to try and take in the combination. I always need to constantly remind myself that ballet takes time, years, to get right. And when I think about giving it up I need to think of this lady, who has clearly done ballet her entire life. That's dedication.