Both:-) Our DD is 6, so that factors into in. Right now she takes piano lessons and has for three years. While she REALLY wants to play the violin, we've told her that she needs to take piano for one more year because we own a piano, she needs to develop a habit for practicing daily and hopefully, she will be able to read music better, so that she can start the violin next year.
She also does children's choir at church and soccer in the fall. That is enough in my opinion. If she gets over scheduled it just means lots of meltdowns and rough nights! She really wants to take dance, but will hold off on that until this winter when we've found a studio that lets you join at any time & no recital!

It's a tough balance. Kids need to be kids, but finding that balance can be hard. Our DD needs days where she can just simply be at home playing.

Good luck!