The first, long lived people will be those who can afford it. Be that from genetic engineering, purchased familial stock, or some kind of controlled living conditions. All of the things in our environment serve to age us, including extremes in temperature, quality of air breathed, and our way of life. That's a lot of moving pieces that must be controlled in order to maximize how long we will live. So, think of the first person to make it to 150 being a test tube baby and adult living in a really sheltered life. It's the only way I can see it done.
But as humans, we still focus medical care and health on treatment too often, and not on prevention.