How early should one consider fat grafting to counter anti-aging?

It is perfectly safe to perform fat grafting at any age. In fact, some craniofacial pediatric anomalies are best treated with fat grafting. Fat grafting can and should be done to achieve a very natural, non-surgical appearance. Fat grafting, just like fillers, is not a one-size fits all approach. Different patient require different amounts The skill and experience of the surgeon performing the procedure is the most important factor in achieving optimal results. Just like with filler or Botox, the patient is paying for the skills of the injector (and not just the product). 

Fat grafting can be performed almost at any age once you are fully developed. For anti aging, I would start with the cheeks and tear trough first. Consult a board certified plastic surgeon in your area for a consult, this way you know you are in the best of hands. Dr T Narsete Denver, Co