If you are set on retiring before you turn 70, I can't give you a definite answer. It depends on a lot of factors, one of which is whether or not you can afford to retire. If you have to retire before age 70, then you should consider retiring as early as possible.
You should start saving for retirement as early as possible. The earlier you start, the more time your money has to grow. And the more time your money has to grow, the more money you’ll have when you retire. It’s as simple as that.
Retirement is a very personal thing. It’s not about how old you are, it’s about how ready you are to stop working. In your case, if you’re 67, I’d say you’d probably be ready to retire in about 30 years.