I have performed a tumym tuck on an 18 year old after massive weight loss but generally prefer not to do so for concerns of future pregnancies. If you have completed your child bearing than I would not see a contra-indication to preceding iwth repair.
It all really depends if you are planning on having any more babies soon. It also depends on your anatomy and if you really need a tummy tuck (abdominoplasty). If you post pictures, we may be able to give you more specific advice. Good luck.