Unfortunately, both dance and theatre are extremely damaging to hair. If you're committed to these things on a long term basis, long hair may not be in your future.

Also, wearing your hair in a ponytail all the time causes tons of breakage, especially if you're using those thin hairties. It's not so much the metal part that damages hair - it's putting the hairtie in the same spot over and over.
    You could try things like wider, seamless hairties or satin scrunchies (be warned, however - the latter will slip out of your hair constantly) or using a headband to hold your hair away from your face while you work out since it's still short at the moment.

When/if your hair grows a bit longer, you can twist it up in the back and bobby pin or clip it into place.

Best of luck.