Okay to go to ballet and taekwondo classes (and spar) before going to ultrasound to determine if palpable abdominal aorta is AAA? Feeling paranoid...

Wait. I would wait to see what is going on first. ballet and taekwondo?? I don't know, you sound like your kind of young for a abdominal aortic aneurism??
Yes and no. ballet may be ok unless you are doing leaps as you would not want to fall, taekwando class definitely not as you should not have any contact with your abdomen till after you ave been cleared for the AAA.